Câu hỏi, câu trả lời.

What is the difference between U.CASH, Uantum AI, and the Una assistant?

U.CASH is the open money network: the pay, swap, buy, names, agents, send, and verify apps plus the portal, all non-custodial. Uantum (uantum.u.cash) is a separate general-purpose AI product that bills per turn in UCASH through the same account. Una (una.u.cash) is a merchant-facing AI assistant that helps U.CASH Pay merchants manage their store and settings conversationally. They are different products that share the U.CASH single sign-on identity and the UCASH billing layer, but they do different jobs. Open →

Can U.CASH recover my funds if I lose access?

No. U.CASH is non-custodial, so it never holds your funds or your private keys. Your money settles on-chain to addresses you control, and on-chain transactions cannot be reversed by anyone, including U.CASH. If you lose access to your wallet or your keys, those funds cannot be retrieved. Keep your seed phrases and private keys backed up somewhere safe: in self-custody, that backup is the only recovery path. Open →

How does U.CASH make money?

U.CASH earns fees on activity across the network: a percentage on payment processing through U.CASH Pay, a 0.30% fee on swaps, per-turn billing on AI agent commerce, and revenue from names, verification, and the wider Ucosystem of apps and services. A portion of network revenue is used to acquire UCASH on the open market, which supports the token economy. U.CASH does not earn by holding or lending user funds, because it never holds them. Open →

Does U.CASH hold, pool, or lend user funds?

No. U.CASH never holds, pools, lends, or rehypothecates user funds, because it never has them. Every payment moves directly from buyer to seller on-chain. The only internal balance on U.CASH Pay is a non-withdrawable fee-credit balance used to pay processing fees, and it cannot be withdrawn as funds. This is the core of the non-custodial model, and it is the reason U.CASH is not a money transmitter under U.S. federal FinCEN rules. Open →

What does non-custodial mean for me?

Non-custodial means U.CASH never holds your funds or your private keys. Payments settle directly to wallet addresses you control, and U.CASH does not pool, lend, or rehypothecate customer funds because it never has them. Your seed phrases and keys stay in your wallet. The practical upside is that there is no central U Balance that can be lost, frozen, or seized; the flip side is that you are responsible for keeping your own keys safe. Open →

Do I need a separate account for each U.CASH app?

No. One U Account, managed at portal.u.cash, works across pay, swap, buy, names, agents, send, and verify. The portal is the single sign-on identity provider: when you sign into any U.CASH app, you are authenticated through the portal and your session spans the whole network. Signing out of one app signs you out everywhere. Open →

How is U.CASH secured?

U.CASH security is architectural: funds settle directly to wallets you control, so there are no U.CASH-held balances to lose. Session cookies are encrypted with AES-256-GCM, and webhooks are HMAC-signed and replay-safe, with a 5-minute timestamp window and constant-time signature checks. Platform APIs carry CSRF protection, and sensitive actions require an authenticated session. Wallet addresses go through sanctions screening at signup and whenever you add a wallet. Card data never touches U.CASH; fiat cards run through your own processor. Open →

What is UCASH used for across the network?

UCASH is the U.CASH network access and loyalty token. It is used to bill AI agent turns in tiny fractions per request, it earns fee discounts on U.CASH Pay based on how much you hold, and it underpins rewards and premium features across the network. Holding UCASH on a verified wallet raises your tier, unlocking lower processing fees and feature gates. UCASH is an ERC-20 on Ethereum, Polygon, and Base; you can buy it at buy.u.cash or swap for it at swap.u.cash. Open →

What apps are part of U.CASH?

The U app drawer carries the twelve core apps: Pay (accept crypto and cards), Swap (exchange), Buy (get UCASH), Sell (cash out to bank), Bridge (cross-chain), Names (your .u name), Agents (agent payments), Portal (your account), Una (AI assistant), Send (mass send), POS (point of sale) and U.CASH AI. Verify (verify your balance and email for perks) rounds out the family. The wider Ucosystem adds the domain industry, Umerce, u.builders, and more. Open →

Is U.CASH custodial?

No. U.CASH is non-custodial by design, so no U.CASH app ever holds your money. Payments settle straight to wallets you control, fiat card payments run through your own merchant account, and swaps settle on-chain to addresses you sign with. Your funds stay yours at every step. Open →

What does 'open money infrastructure' mean?

U.CASH describes itself as the open money layer for the open internet. In practice that means a shared set of non-custodial payment, swap, and identity rails that any application, merchant, or AI agent can build on, across 30+ chains. Instead of one closed payments company holding your funds, U.CASH provides open APIs, signed webhooks, SDKs, and open standards like UCP and HTTP 402, so money moves the way information does on the open web. Open →

What is the u.cash website?

u.cash is the U.CASH product hub: the central site that ties together the family of apps living on the *.u.cash subdomains, including pay, swap, buy, names, agents, send, verify, and the portal where your account lives. The hub explains the open-money thesis, lists the apps, covers the UCASH token and the network economy, and links to developer resources. One account works across every app. Open →

What is the difference between U.CASH and U.ONLine?

U.CASH (u.cash) and U.ONLine (u.onl) are complementary siblings under the Ucosystem umbrella. U.CASH is the open-money and payments infrastructure: the pay, swap, buy, names, agents, send, and verify apps, all non-custodial, across 30+ chains. U.ONLine is the business-apps infrastructure: B2B and B2C commerce, services, AI tools, and related business applications. UCASH is the network access and loyalty token running through both, and revenue from across the Ucosystem feeds the U.CASH economy. Open →

What is the Ucosystem?

The Ucosystem is the umbrella over U.CASH, U.ONLine, and a broad network of decentralized and centralized apps, agents, and services. It organizes everything into four infrastructures: DNS (domains and identity), Crypto (payments and assets, which is U.CASH), AI (agent payments), and Apps (business applications, which is U.ONLine). Revenue from across the entire Ucosystem flows into and supports the U.CASH economy and the UCASH token. Open →

What is U.CASH?

U.CASH is open money infrastructure: a non-custodial network of apps for pay, swap, buy, names, agent payments, send, and verify, all running across 30+ blockchains. The internet runs on open protocols for everything except money, and U.CASH is the open money layer any app or agent can build on. One account works across every app, and funds always settle to wallets you control. U.CASH has been active since 2015. Open →

I see an insufficient balance or insufficient funds error. What do I do?

This just means the wallet or account does not have enough of the required asset to complete the action, and it is easy to fix. For a swap, top up the input token in your connected wallet and make sure you also have enough of the chain's native token (for example ETH on Ethereum) to cover gas. For an AI agent or U.CASH Pay fee-credit action, add credit or UCASH to your account balance. Also double-check the asset and the network: a token on the wrong chain will read as zero balance even if you hold it elsewhere, and nothing is lost when that happens. Open →

I see an invalid address error. What does it mean?

It means the wallet address you entered is not valid for the cryptocurrency or network you selected. Each chain has its own format: Bitcoin addresses look different from Ethereum (0x...) addresses, which look different from Solana addresses. Check that the address matches the coin and the network, that you pasted the full address without truncation, and that you are not sending a token on the wrong chain. U.CASH can also resolve ENS, Unstoppable Domains, and FIO names to the correct wallet, so a human-readable name is a safer way to send. Open →

My wallet was rejected as not allowed. What happened?

U.CASH runs sanctions screening on wallet addresses at signup and whenever a wallet is added, and the list refreshes daily. If a wallet is on the list, it cannot be used on U.CASH and you will see a neutral message saying the address cannot be used. If you believe a wallet was flagged in error, contact support through the portal or hello@u.cash and it will be reviewed. The screening applies only to addresses used on U.CASH; your on-chain funds are unaffected and remain fully under your control. Open →

A payment link shows transaction not found. What do I do?

This usually means the payment link is expired, was already completed, or the token in the link no longer resolves to a store, and none of those put your funds at risk. First check that you opened the full, untruncated link and that it has not expired. If you are the merchant, verify your store's cloud token is still valid in your pay.u.cash dashboard. If you are a buyer, ask the merchant to generate a fresh link. Because U.CASH is non-custodial, nothing was ever held, so a stale link cannot trap your money. Open →

How do I get support or contact U.CASH?

The best way to get support is to start a ticket at pay.u.cash/support or email support@u.cash. For anything tied to your account, sign in at portal.u.cash or pay.u.cash. Email routing: - hello@u.cash for general questions - partners@u.cash for partnerships - press@u.cash for press and media - security@u.cash for security reports Account questions cannot be handled over public channels, because U.CASH is non-custodial and account access is self-managed through the portal. Open →

How do I get started with U.CASH?

Create one account at the U.CASH portal, portal.u.cash. That single login works across pay, swap, buy, names, agents, send, and verify, so there are no separate signups per app. Then connect wallets you already control (Bitcoin xpubs, EVM addresses, Solana, Tron, and more) and start in whichever app fits: accept a payment at pay.u.cash, swap at swap.u.cash, buy UCASH at buy.u.cash, or claim a .u name at names.u.cash. Open →

I lost my 2FA device or authenticator. What do I do?

When you enrolled two-factor authentication at the portal, you were given one-time backup codes: use one of those to sign in, then re-enroll a new factor. If you enrolled a passkey on another device, you can sign in with that instead. If you have neither backup codes nor another factor, contact support via the portal or hello@u.cash to start an account-recovery review. Note that 2FA protects your U.CASH login only; it does not control your on-chain funds, which remain accessible to whoever holds your wallet keys. Open →

I lost my password. How do I recover my account?

Use the Forgot password link on the portal.u.cash sign-in page and you will receive a reset link by email. U.CASH cannot see or change your password for you. Recovering your portal password restores access to your account dashboard and settings; it does not recover your crypto wallets, because funds are on-chain and controlled by whoever holds the wallet keys, independent of your U.CASH login. Open →

My payment is stuck pending or confirming. What should I do?

A payment stays pending until it reaches the required number of block confirmations for its coin, so a wait is usually normal, not a loss. Slow confirmation typically means network congestion or a low gas fee on the sender's transaction. You can check the transaction on a public block explorer for that chain to watch its progress, and if it is confirmed on-chain but still pending in U.CASH, allow a few minutes for detection. For U.CASH Pay, the merchant's per-coin confirmation policy sets the threshold, so you can ask the merchant or check your own store settings. You cannot speed up an on-chain transaction from U.CASH. Open →

How do I report a security vulnerability?

Email security@u.cash with details before any public disclosure so the team can investigate and fix it; U.CASH follows responsible disclosure. The plugins and SDKs are open source in U.CASH's public repositories, so you can review the code and file issues there too, and u.cash/developers points you to them. Please do not report security issues over public social channels. Open →

Which app should I use first?

It depends on your goal. To accept payments from others, start with U.CASH Pay (pay.u.cash). To trade one crypto for another, start with U.CASH Swap (swap.u.cash). To acquire the UCASH token, start with U.CASH Buy (buy.u.cash). To get a web3 identity like a .u name, start with U.CASH Names (names.u.cash). All of them share one account, so the rest are one click away once you sign in. Open →

Which apps are in the U.CASH drawer?

The U app drawer carries the twelve core apps: Pay (accept crypto and cards), Swap (exchange), Buy (get UCASH), Sell (cash out to bank), Bridge (cross-chain), Names (your .u name), Agents (agent payments), Portal (your account), Una (AI assistant), Send (mass send), POS (point of sale) and U.CASH AI. Open the drawer from the menu of any U app; everything signs in with your one U account. Open →

Is U.CASH accessible? Does it support accessibility needs?

U.CASH web apps are built with accessibility in mind: semantic HTML, keyboard navigation, skip-to-content links, ARIA labels on interactive controls, and a theme toggle for dark and light modes. The coin network pages and apps follow the same shared stylesheet and component patterns. If you hit an accessibility barrier in a specific app, please report it via the contact page or hello@u.cash so it can be addressed. Open →

How are my sessions protected?

Your U.CASH session cookie is encrypted with AES-256-GCM, an authenticated encryption mode, which means a stolen cookie alone is not enough to act on your account. Sessions have an idle timeout and an absolute expiry, and login is protected by rate limiting and lockout to block brute force. Sensitive operations, like rotating API keys or changing payout addresses, can require a recent step-up authentication if you have a second factor enrolled. Open →

Is my data private? What does U.CASH store about me?

U.CASH stores only what is needed to operate the platform: your account email, the wallet addresses you connect, transaction records for settlement indexing, and your notification preferences. It does not require or store government IDs, and each merchant's data lives in an isolated database. Wallet addresses go through sanctions screening for abuse prevention. See the privacy page for the full details on what is collected and why, and reach hello@u.cash with specific requests. Open →

What are the fees across the U.CASH network?

There is no monthly subscription. U.CASH Swap charges a flat 0.30% on swaps. U.CASH Pay charges a small platform fee per transaction, and UCASH holders get a discount. Fiat card payments run through your own merchant account, so card fees are set by your card processor, not U.CASH. AI agent turns are billed per request in tiny fractions of UCASH or prepaid credit, and you also pay the on-chain gas fee for the chain you transact on. Check each app for its exact current rate. Open →

Who pays the network (gas) fee?

On U.CASH Pay, the buyer sends a real on-chain transaction to the seller's wallet, so the buyer pays the network (gas) fee for their own chain. For swaps at swap.u.cash, your wallet signs the swap and pays the gas for the chain you transact on. For agent payments over the gasless exact (EIP-3009) rail, the buyer signs an off-chain authorization and a platform relayer submits the on-chain transaction, so the buyer pays no gas; the seller is billed the relayer's gas plus a small margin. U.CASH itself does not subsidize gas except through that relayer path. Open →

How does one account work across all the apps?

portal.u.cash is the U.CASH identity provider, and each app (pay, swap, buy, names, agents, send, verify) is a relying party. When you sign into an app, it delegates authentication to the portal over a signed, single-use code exchange, then issues a shared session cookie scoped across u.cash. You log in once at the portal and every app recognizes you. The same factor (password, TOTP, or passkey) protects every app. Open →

How many integrations and plugins does U.CASH have?

U.CASH has 125+ open-source plugins, SDKs, and integrations, and all of them are non-custodial, so funds settle direct to your wallet. They cover e-commerce (WooCommerce, Shopify, Magento 2, BigCommerce, PrestaShop, and more), billing and invoicing (WHMCS, Invoice Ninja, QuickBooks, Xero), point of sale, memberships, donations, creator platforms, chat and social bots, automation (Zapier, n8n, Make), AI agent frameworks (LangChain, LlamaIndex, crewAI), and native mobile frameworks. Browse the full catalog at u.cash/integrations, including the community-maintained awesome-ucash list in the public repositories. Open →

Does U.CASH require KYC (identity verification)?

No. U.CASH does not require or store government IDs, and because it is non-custodial and never holds your funds, it does not run a KYC program on its users. Wallet addresses do go through sanctions screening at signup and when wallets are added. Some third-party partner services you can reach through U.CASH, such as the instant-exchange provider behind some swaps, may have their own KYC requirements under their own terms. Open →

Does U.CASH have a mobile app or is it desktop only?

U Apps are web apps that work in any modern browser on desktop and mobile, and they are designed mobile-first, so there is nothing separate to install. You use them at pay.u.cash, swap.u.cash, and the other app domains. Web3 wallet features use the wallet extension or mobile wallet app you already have. For developers, platform SDKs (React Native, Flutter, Swift, Android) make it possible to embed U.CASH payments inside native mobile apps. Open →

Is there a monthly subscription or recurring fee?

No. U.CASH apps do not require a monthly subscription or recurring membership. You pay per use: a percentage fee on swaps and payment processing, per-turn billing for AI agents, and the on-chain gas fee for your transactions. Some premium features on U.CASH Pay unlock based on your lifetime account activity rather than a subscription. Open →

Where is the U.CASH roadmap or whitepaper?

U.CASH does not publish a single traditional whitepaper. The closest equivalents are the Economy page, which explains the UCASH token, the Ucosystem revenue model, and how network revenue feeds the token, and the Technology page, which covers settlement, multi-chain routing, webhooks, and confirmations. The About page covers the company story from 2015 onward. For developer direction, the open standards (HTTP 402 and UCP) and U.CASH's public open-source repositories reflect what is being built. Open →

Where is the U.CASH status page?

The status directory is at u.cash/status. It lists what is running and where to check each service directly, rather than publishing synthetic uptime percentages. If a service looks degraded, the fastest way to confirm is to open the app itself or start a ticket at pay.u.cash/support. For Pay-specific operational status, see pay.u.cash/status. Open →

How many blockchains and tokens does U.CASH support?

U.CASH supports 30+ blockchains out of the box, including Bitcoin, Ethereum, Solana, Tron, Polygon, Base, Arbitrum, Optimism, BNB Chain, and Avalanche, plus 12 newer EVM chains: - Linea, Mantle, Berachain, Sonic, Unichain, Worldchain, Monad, Plasma, Abstract, HyperEVM, Scroll, Ink, Robinhood Chain, and Arc You can also add any custom token across 22 networks (ERC-20, BEP-20, Base, Polygon, Arbitrum, Optimism, TRC-20, SPL, and more). U.CASH Swap reaches 1,500+ swappable coins, and UCASH itself lives on Ethereum, Polygon, and Base. Open →

Which countries or regions does U.CASH support?

U.CASH is internet-native and is not gated by country: the apps are reachable globally and crypto settlement works wherever the underlying blockchains do. Because U.CASH is non-custodial and does not hold fiat, it does not impose per-country access the way a fiat on-ramp would. You are responsible for complying with your local laws, including any restrictions on crypto use and your tax reporting obligations. Some partner services, for example instant-exchange providers, may have their own regional restrictions and KYC requirements. Open →

Does U.CASH provide tax reporting or statements?

U.CASH does not issue tax forms and does not report to tax authorities. You can view and export your transaction history from each app, for example the Pay dashboard and Swap history. Because crypto transactions are taxable events in many jurisdictions, you are responsible for keeping your own records and reporting accurately. U.CASH recommends consulting a tax professional familiar with cryptocurrency in your country. Open →

Who founded U.CASH, and who is on the team?

U.CASH was started in 2015 by an independent team. You can read more about the story and the people behind the network on the About page. Open →

Which blockchains does U.CASH support?

U.CASH supports 30+ chains out of the box, including Ethereum, Polygon, Base, Bitcoin, Solana, Tron, and more. For payments it covers native L1s (BTC, ETH, SOL, TRX, XRP, LTC, DOGE, BCH, XMR, ALGO, DOT, XLM, XTZ, TON) plus EVM chains (Base, Arbitrum, Optimism, Polygon, BNB Chain, Avalanche, Linea, Mantle, Berachain, Sonic, Unichain, World Chain, Monad, Plasma, Abstract, HyperEVM, Scroll, Ink, Robinhood Chain, and Arc). You can also add any custom token by wallet plus contract across the supported networks. Open →

How does prepaid credit billing work?

U.CASH Pay runs on a prepaid credit model. You load funds once with Add Funds, and that balance pays for platform fees, POS registers and other account costs as they happen. Every charge is recorded with its amount, percentage, transaction, currency and date, so your credit balance is always reconcilable against real activity. Top up any time from the Account area. Open →

What will I see on the checkout page?

The checkout shows the product title, the amount, and a grid of accepted coins grouped by network (Ethereum, Base, Solana, TRON, native, and so on). Pick a coin and the page shows the receive address, a QR code, the exact crypto amount, and a countdown timer. If you have MetaMask, TronLink, or Phantom connected, a one-tap wallet button and your balance appear too. The page keeps checking the chain and switches to a confirmation screen when your payment lands. See pay.u.cash/about. Open →

What are Converters?

Converters are retail merchants who use U.CASH Pay to move cash and crypto in both directions for their customers, through the Payout Info Request and payment-link features. It is the human, retail fiat on/off-ramp: you bring cash and the converter sends you crypto, or the reverse, and the platform tracks the request. This is different from swap.u.cash, which does on-chain crypto-to-crypto token swaps with no cash involved. Open →

Does my payment go straight to the merchant?

Yes, immediately in principle: you pay the merchant's wallet directly on-chain. The sale is marked settled once the payment reaches the required number of confirmations for that coin. There is no payout queue and no withdrawal for the merchant to wait for, because the money was never anywhere but their wallet. Open →

Is U.CASH Pay a money transmitter?

No. Because the platform never holds customer funds (payments go direct from buyer to seller), it is not a money transmitter or a custodian. It is payment infrastructure. As with any payments service, each user remains responsible for their own regulatory compliance in their jurisdiction. Open →

What does non-custodial mean when I pay?

Non-custodial means U.CASH Pay never holds funds or private keys. Your payment travels direct from your wallet to the merchant's own wallet on the blockchain. The platform only reads the chain to confirm the payment happened and then notifies the merchant. Because no custodial account sits in the middle, there is nothing to lose, freeze, or be robbed of. Open →

What is a Payout Info Request?

A Payout Info Request is a built-in over-the-counter flow for paying someone out in cash or crypto. You send the payee a secure no-login link, they submit their wallet address or payout email, and you settle the cash or crypto leg with them in person, off-platform. When it is done you mark the request as sent to complete the record. It is a handy desk for converting cash to crypto and back through you as the merchant. Open →

How does pos.u.cash integrate with pay.u.cash?

pos.u.cash is the point-of-sale side of your pay.u.cash account, and it is managed entirely from your pay.u.cash dashboard. The POS panel is where you add and remove registers and save POS settings, and every register uses the same account, wallets and branding you already configured. A customer-facing register runs from its own display link, so a browser or tablet at the counter needs no merchant login. Open →

Can I use U.CASH Pay to sell on my website or online store?

Yes, three ways. Embed a Pay button on any site with one script tag, integrate the REST API or a store module into your existing shop, or use the built-in Shop storefront as a hosted online store with products, discount codes and digital license-key delivery. All of it is non-custodial, so funds settle direct to your wallet. Open →

Does U.CASH Pay have a storefront / shop page?

Yes. The Shop Page is a full hosted storefront: pick from 16 layouts, then configure a hero, navigation, content sections, footer columns, social links, an announcement bar and custom pages. Products are checkouts with extra fields such as badge, category, compare-at price and CTA label, and per-product imagery, discount codes and license keys are all supported. It renders at /shop on your account or on your custom domain. Open →

I want to convert one crypto to another. Is pay.u.cash or swap.u.cash the right app?

Use swap.u.cash for that. pay.u.cash is for payments: merchant checkouts, invoices, storefronts, and Converter cash-to-crypto services. swap.u.cash is a non-custodial DEX aggregator for on-chain crypto-to-crypto token swaps across 18+ EVM chains, plus instant-exchange. They are separate products: pay moves money for goods and services, swap converts one token into another. Open →

What is U.CASH Pay?

U.CASH Pay (pay.u.cash) is a non-custodial crypto payment platform. When you pay a store that uses it, your crypto goes straight from your wallet to the merchant's wallet on the blockchain. The platform watches the chain to detect your payment, marks the order settled once it reaches the required confirmations, and notifies the merchant's store. It never holds your funds or anyone's private keys, so it is payment infrastructure, not a bank or a money transmitter. Learn more at pay.u.cash/about. Open →

What is pos.u.cash?

pos.u.cash is the U.CASH point-of-sale app for taking payments in person. It is built on the same rails as pay.u.cash, so your customers can pay in crypto or by card while the money settles straight to your own receive wallet. You sign in with your merchant account and run a register from any device with a browser. Open →

Where can I see the fees I have been charged?

Your dashboard has a fee history view that lists every fee charged to your account. Each entry shows the amount, the fee percentage, the transaction it came from, the currency and the date. POS register purchases and per-transaction platform fees all appear here, so you can reconcile your credit balance against actual activity. Open →

Can I customize the branding (logo, colors, CSS)?

Yes. Set your brand name ($5 lifetime tier), payment page logo ($15), custom colors ($20) and custom CSS ($25). Dark and light logo variants plus a custom favicon are supported. Your checkout and shop pages pick up the theme automatically. Open →

How do I cancel a payment I started?

If you have not sent any crypto yet there is nothing to cancel: just close the page and the order expires on its own when the timer ends. Nothing is ever charged until you actually send from your wallet. If you already sent, the payment went straight to the merchant's wallet and cannot be reversed by the platform, so contact them about a refund. On the merchant side, cancelling a pending transaction releases the receive address back to the address pool for reuse and deletes any shop license keys tied to the order; completed (C) or underpayment (X) transactions cannot be cancelled that way. Open →

How do I create a payment link?

In your dashboard go to Create Checkout (or Payment Request). Set a title, price, currency, optional description, redirect URL, and the coins to accept. You get a shareable /checkout/your-slug link plus an opaque encrypted /checkout/token link, both hosted on pay.u.cash or your custom domain. Send the link by email, chat or invoice; the buyer opens it and pays. Open →

How do I sign up and create my first store?

Go to pay.u.cash and click Sign up free (U.CASH portal registration) or Login with U. After signing in, the dashboard walks you through connecting a wallet for each coin you accept, setting branding, and creating your first checkout or shop product. There is nothing to install; your account and store live on pay.u.cash. Open →

How do I top up my credit balance?

In your Account area choose Add Funds (credit) or Buy UCASH. This creates an encrypted payment link for the amount, which you pay on-chain like any checkout. Once confirmed, your credit balance is topped up and the amount counts toward the lifetime funding total that unlocks features. Fees and account costs are then drawn from that balance. Open →

Can I upload files like CSV or text data?

Yes, in specific places: - Lander import: bulk import landing pages from CSV under Settings -> Import in pay.u.cash. - Transaction export: download your transactions as CSV or text from the dashboard. - Mass sends: upload a CSV of addresses and amounts on send.u.cash. There is no general file upload for branding graphics; use the dashboard logo setting or a logo URL instead. Open →

Can I run the checkout on my own domain?

Yes. The Custom Domain feature is a $50 lifetime-spend tier unlock, reached either by $50 in total Add-Funds top-ups or by holding enough UCASH to qualify for the equivalent tier. Enter your domain, point a CNAME record at pay.u.cash, and SSL is provisioned automatically. While active it costs $0.50 per month from your prepaid credit, and you can toggle it on and off; it auto-suspends if the tier lapses. Open →

Can I turn my custom domain on and off, and what happens if my tier lapses?

Yes, there is an on/off toggle on the custom-domain row. Active means the domain is enabled, the feature is unlocked, a domain is set, and the account is funded. If the tier lapses, for example UCASH holdings drop below the threshold, the domain auto-suspends: it stops routing and stops billing, but the domain is kept in your settings so toggling back on after re-qualifying re-provisions the same domain. The toggle is your intent; tier and credit are automatic gates. Open →

Can I use a custom block explorer or address source?

Yes. The custom explorer integration lets you plug in your own explorer endpoint for address generation and lookup, using a templated URL and a JSON path to the address. It is useful for long-tail coins or for running your own private explorer. See the custom explorer guide. Open →

Can I collect custom fields or customer details at checkout?

Yes. Checkout custom fields ($30 lifetime tier) add extra inputs to your payment page, and required user details ($35 tier) make customer information mandatory. Responses are stored on the transaction and visible in your dashboard. Common uses are order notes, account numbers or delivery details. Open →

Can I accept my own ERC-20 or custom token?

Yes. Under Custom Tokens in your dashboard, add a code, name, contract address, network, decimals, and the receive wallet you control. Supported networks include Ethereum, Base, Polygon, Arbitrum, Optimism, Avalanche, BSC, Solana, Tron, TON, Linea, Mantle, Berachain, Sonic, Unichain, Worldchain, Monad, Plasma, Abstract, HyperEVM, Scroll, Ink, Robinhood Chain and Arc. Incoming transfers are detected on each chain and credited like any built-in coin. See the custom token guide. Open →

How do I actually pay an invoice or payment link?

Open the link and pick a coin. Then either scan the QR code with a mobile wallet, copy the address and the exact amount into your wallet, or tap the MetaMask, TronLink, or Phantom button to pay straight from your browser wallet. Send the exact crypto amount shown. Stay on the page: it keeps polling the chain and switches to a confirmation screen once your payment lands and reaches the required confirmations. Open →

Can I embed a Pay button on my own website?

Yes. Paste a single script tag into your page that points at https://pay.u.cash/embed.js and carries data attributes for your store token, amount, currency, title and redirect URL. It renders a styled Pay with U.CASH button; clicking it creates the checkout server-side and sends the buyer to the hosted payment page. There is no CORS setup and no client-side API key, and it works on any site. Open →

The checkout shows no payment methods, but works in incognito. Why?

This is almost always a stale login cookie, not a problem with the store. If you have a U.CASH account, an old cookie can make the checkout load your account instead of the store, and your account has no receive addresses to show. Fix it by clearing the site's application data (the pay.u.cash cookies) and reloading, or simply keep using the private window that already works. The coin grid should be back straight away. Open →

My checkout expired before I paid. What now?

Nothing went wrong and no funds were taken. When the countdown hits zero the order is marked expired, the receive address is released back to the pool for reuse, and you see an expired screen. Just start a fresh payment: you get a new address and a new rate quote. If you had already sent crypto before expiry, it still lands in the merchant's wallet, but the platform will not auto-match it to the expired order, so tell the merchant right away. Open →

How do I host my logo image to get a URL?

Any public image URL works for your logo. The easy routes: - Upload the logo directly in your pay.u.cash dashboard under Settings -> Branding. - Use an image already hosted on your own website or server and copy its public URL. Then paste the URL into Settings -> Branding so the checkout and shop pick it up. Make sure the link opens the image file itself, not a gallery page. Open →

Can I generate an invoice or tax receipt?

Yes. With Invoicing unlocked ($10 lifetime tier), a completed transaction with billing details can generate a branded PDF tax invoice, and the invoice-number prefix is configurable. Buyers can also enter billing details on the payment page and download the invoice themselves. VAT and tax calculation is supported with country-code rates and VAT-number validation. Open →

I sent crypto just after the timer hit zero. Where did it go?

Your crypto arrived safely: payments always go direct to the merchant's wallet address, never to U.CASH. The catch is that the platform will not auto-match a payment to an order that already expired, so the merchant has to sort it out manually. Contact them with your TX hash and they can either complete the order for you or refund you. Next time, send within the countdown window so the payment matches automatically. Open →

How does the Payout Info Request flow work step by step?

The flow is five steps: - Create the request with an amount, coin or fiat, a note, and the payee's email. - The payee gets a no-login link and submits their wallet address or payout email; Web3 names such as ENS are accepted and resolved. - You are notified once they have submitted. - You settle the cash or crypto leg in person, off-platform. - You click Mark as Sent, which completes the record and meters the fee. Open →

Where do the funds go? Do I set my own receive wallet?

Funds go direct to your own wallet. You set a receive address per coin under Payment Options, or use address generation such as a BTC xpub or derived Ethereum addresses; generated addresses are HD-derived. The platform never holds or moves the payment, so money arrives on-chain to your wallet as payments confirm and there is no platform-held balance to wait on. Open →

Will I be taken back to the store's site after paying?

Usually yes. The merchant can set a redirect URL on the checkout or per transaction, and integrations can stamp one on per order. On successful completion you are redirected there automatically. The shop app and embedded checkouts both support this. Open →

How do I refund a payment?

Open the transaction in your dashboard and use Refund. The platform reads the original on-chain transaction to find the sender's address and amount, then sends the funds back using a refund method you have enabled: on-chain node refunds for BTC and Ethereum, or exchange-based refunds. The amount and sender must match exactly. Refunds are off by default, so enable a method in settings first. Open →

How do I brand my checkout (brand name, logo, colors)?

Branding lives in the dashboard under Settings. Brand name displays your brand instead of U.CASH Pay and unlocks at the $5 lifetime tier, the payment page logo at $15, custom payment form colors at $20, and custom CSS for the payment page at $25. Each one has an on/off toggle, so you can disable a field without clearing it; toggled off, the checkout falls back to defaults. Your payment and shop pages pick the theme up automatically. Open →

How do I add a product to my shop?

A product is just a checkout with shop fields turned on. In the Shop section, create a checkout and set its price, title, image, category, badge, compare-at price, and CTA label. It appears in your storefront grid, optionally filtered by category section, and buyers click through to the normal checkout flow to pay. Open →

How do I sign in to pay.u.cash?

Sign in at pay.u.cash with your U account - the same single sign-on you use across every U.CASH app. If you already use portal.u.cash or any other U app, you are already registered: just use the same credentials, and creating a store takes only a few clicks after that. Open →

Should I send to the same address I used last time?

No. Always pay the address shown on your current checkout, never one copied from an earlier order. Merchants can enable a stop-reusing-addresses setting so every order gets a fresh address from the pool and none is ever recycled. Combined with address generation, that gives a unique address per payment without manual management. Open →

The checkout is stuck on 'Confirming your payment'. Did my payment go through?

Almost certainly nothing is wrong. If your transaction has fewer than the required confirmations the screen is simply waiting, and busy networks can take a bit; the page polls on its own and should update within a few polls. Try refreshing it, and check the transaction in your own wallet or on any block explorer using its hash. If it shows confirmed there but the page still says confirming, contact the merchant: once their side shows status C (complete) your payment has settled and only the display is lagging. Open →

Can I upload a logo or image for my store?

Yes. Set your logo in the dashboard under Settings -> Branding, either by uploading it there or by pasting any public image URL. If you use a URL, it must point directly to the image file, ending in .png, .jpg, .svg or .webp. Dark and light logo variants are supported for the payment page. Open →

How do I verify my UCASH holding for the discount?

In your Account area, connect the Ethereum wallet holding your UCASH and sign a message (MetaMask personal_sign; no gas, no transaction). The platform recovers the address from the signature, reads your on-chain UCASH balance across all linked wallets, and caches the tier you qualify for, re-checked on each login. Holding UCASH is the second unlock path: the top tier unlocks all spend-tier features, lower tiers scale proportionally, and you can qualify by lifetime top-ups instead. Every UCASH tier also carries a percentage discount on your platform fee, applied on top of your volume tier. Open →

How do I get started with POS?

Sign in at pos.u.cash with the same merchant account you use for pay.u.cash. If you do not have a merchant account yet, create one at pay.u.cash first, set your receive wallet and the coins you accept, and then your store is ready to use in POS too. Register billing follows the same per-register pricing shown in your pay dashboard. Open →

How does a POS register work at the counter?

Enter the amount to charge and the register shows your customer a QR code they can scan with their wallet, plus wallet button options. The screen updates live as the payment is detected and confirmed on-chain, so you and the customer both see when it is complete. Every sale lands in your merchant dashboard alongside your online payments. Open →

Why did I get a different receive address from last time?

Some merchants generate a fresh receive address for every order, which makes payments easier to tell apart and improves privacy. Generation can run from a BTC public key (xpub), an Ethereum node, or a custom explorer endpoint. Without it, the platform reuses a single address per coin and tells simultaneous payments apart with a tiny unique amount suffix. Either way, just pay the address shown on your current checkout. Open →

Why is the crypto amount such an odd, precise number?

When the merchant uses a single shared receive address for a coin, the platform adds a tiny randomized suffix to the crypto amount so it can tell two simultaneous payments apart. The fiat price you were quoted is unaffected; only the on-chain crypto amount carries that marker. Send exactly the amount shown, down to the last decimal, so your payment matches your order. Merchants can avoid this entirely by enabling address generation. Open →

What bank and payment-app rails can a checkout offer?

Alongside 56 crypto assets, a checkout can offer cards through the merchant's own Stripe, PayPal or 2Checkout account, and 22 manual bank rails: ACH and domestic wire (United States), X Money (X app @handle or ACH), Cash App ($cashtag), Venmo (@handle), Zelle (email or phone), SWIFT (international), SEPA (Eurozone), Interac e-Transfer (Canada), Faster Payments (UK), PayID (Australia), PIX (Brazil, instant 24/7), UPI (India, instant), Alipay and WeChat Pay (China), PayNow (Singapore), PromptPay (Thailand), FPS (Hong Kong), M-Pesa (East Africa) and TWINT (Switzerland, instant) and MTN MoMo (Ghana, instant) and MoMo Vietnam (Vietnam's largest e-wallet), plus unlimited custom rails. Buyers send the payment from their own bank or app to the merchant's coordinates, the order holds for 30 days with a unique payment reference, and the merchant confirms it in Payments with one click. No processor account is needed and funds never touch the platform. Open →

Can I pay by credit or debit card?

Sometimes. A merchant can enable card payments through their own card processor account. If you choose the card option you leave the crypto checkout and pay in fiat on the processor's page; once that settles in the merchant's account (minus the processor's fees), the order is marked complete and the merchant's store is notified. This is the merchant accepting fiat by card, not a way to buy crypto with a card. Open →

How does the checkout show confirmation progress?

Once your on-chain transaction is detected, the screen switches to a confirming state showing confirmations / minimum (for example 2 / 3) ticking up. A 'Confirmed' badge appears when it crosses the threshold. The page checks every few seconds, and every second for Lightning. Leave the tab open and it updates on its own. Open →

How many confirmations does my payment need?

Each coin has its own confirmation count, with a default of 3. The merchant can set it per coin, and a custom token can carry its own value. A high-value payment can require more: the merchant sets a confirmations-increase threshold (a USD fiat value) and the count multiplies by a percentage once a payment crosses it. Your order settles only once the on-chain transaction reaches the required confirmations. Open →

Why is there a countdown timer on the checkout?

The countdown is your payment window, set by the merchant's refresh interval (default 30 minutes). Send your payment before it hits zero. When it reaches zero the order is marked expired and the address is released for reuse, so an old address may belong to a different order later. The timer exists because exchange rates move and addresses get recycled; it keeps the quoted amount valid. Open →

What happens if my credit balance runs out?

If your balance cannot cover the fee for a sale, the platform blocks that payment with a friendly message telling the buyer the option is unavailable right now and to contact you, and it emails you so you know. The transaction is not created, so your balance never goes negative. Top up to resume; the Add Funds links themselves are always exempt. Open →

Can another merchant steal or overwrite my custom domain?

No. Every custom domain is ownership-guarded: if a host is already connected to another account, any new claim is refused outright before anything changes. Clearing or deprovisioning a domain is only possible from the account that connected it, so nobody can overwrite your entry or knock your domain offline. Your domain stays yours. Open →

How is SSL provisioned for a custom domain?

SSL is provisioned automatically for custom domains. Point a CNAME record at pay.u.cash, and a certificate is issued and kept renewed for your domain with no manual steps on your side. While the custom domain is active it costs $0.50 per month from your prepaid credit. Open →

Do I need an account to pay?

No. You do not need a U Account to pay. Open the payment link, pick a coin, and pay from your own wallet. Only the merchant has an account; to the platform you are simply a wallet making a payment. The merchant can optionally collect your details through custom fields on the checkout. Open →

Does U.CASH Pay keep a customer list?

Yes. When a buyer provides an email, at checkout or through custom fields, a customer record is created or updated in your account. The dashboard lists customers with their transaction history and shop points, and you can search and manage them. Customers belong to your merchant account only. Open →

What does the merchant dashboard show?

The dashboard is your merchant home base. It shows your transactions, checkouts, balances and payouts, plus your shop, point-of-sale registers, customers, settings and analytics. Everything you need to run the account day to day sits one or two clicks from the front page. Open →

How does the checkout know I have paid?

The platform reads the blockchain through public explorer APIs and, for newer chains, direct RPC. It scans the receive address for incoming transfers matching your order amount, and it can also follow a transaction hash submitted by your wallet button. A per-minute background check and your browser's polling both run, and the first one to confirm the transaction marks the sale as credited. You usually do not need to do anything except keep the page open. Open →

Can I offer discount codes?

Yes. In the Shop section you create discount codes for a percentage or a fixed amount off, with optional usage limits. Buyers enter the code at checkout, the platform validates it, and the discount is applied to the price before the crypto amount is computed. Open →

Why do some payment links look readable and others look like random characters?

Every checkout has two shareable /checkout/ links. The readable one uses the slug or numeric id, like /checkout/my-product. The encrypted one is an opaque token that hides the id but resolves to exactly the same checkout. Both still require the store's cloud token in the URL to load, so access is gated the same way for both. Open →

Where does the exchange rate on my payment come from?

For external-rate cryptos like BTC and ETH, the base price comes from a major exchange feed; fiat cross-rates come from a fiat rate service and are cached hourly. Custom tokens can carry a fixed rate or a rate URL the platform fetches. UCASH uses the platform's configured price (default $0.0021 per UCASH). Rates are expressed as crypto per unit of fiat, so the checkout shows you the exact on-chain amount for the fiat price. Open →

Can I verify my payment on a block explorer?

Yes. Every payment has a TX hash that identifies it on its chain, and the transaction detail on the platform side includes a clickable explorer link for it. You can also copy the hash from your own wallet's history and paste it into any block explorer for that chain. Matching the hash is the surest proof your payment went through. Open →

What happens if my transaction fails or reverts on-chain?

On EVM chains the platform reads the transaction receipt status, and Solana failed transactions are detected too. A failed or reverted transaction is shown to you as 'No payment': 'The transaction failed on the blockchain. No funds were taken; please try again.' The order is left open rather than deleted, so if the transaction genuinely confirms later it can still be credited. Nothing was taken from you, so you can simply try again. Open →

What are the volume-based fee tiers?

Your fee rate is set by your total processed volume each month and drops automatically: $0-$99.99 = 0.50%, $100-$249.99 = 0.45%, $250-$499.99 = 0.40%, $500-$999.99 = 0.35%, $1,000-$2,499.99 = 0.30%, $2,500-$4,999.99 = 0.25%, $5,000+ = 0.20%. The minimum fee per transaction is $0.01. See the pricing page. Open →

What fees are involved when I pay?

As the payer, your only cost is the normal network fee your wallet charges. The U.CASH Pay platform fee is charged to the merchant, never added to your payment: a small percentage of monthly transaction volume, tiered from 0.50% under $100/month down to 0.20% at $5,000+/month, with a minimum of $0.01 per transaction. It is debited from the merchant's prepaid credit balance when a sale settles, not taken out of the payment itself. There is no monthly fee, setup fee, per-seat charge, or payout fee anywhere in the flow. Details at pay.u.cash/pricing. Open →

Can I charge a flat fee per transaction?

Yes. Flat Fee ($40 lifetime tier) adds a flat amount on top of the percentage for every transaction, and the per-checkout fee override ($45 tier) sets a custom percentage or flat fee for a single checkout. These surcharges are added to the price the buyer pays. The platform fee itself is still debited from your credit balance. Open →

What are the funding tiers and what do they unlock?

Every dollar you load to run your account counts toward a lifetime total that permanently unlocks features: $5 Brand name, $10 Invoicing and tax/VAT, $15 Payment page logo, $20 Custom colors, $25 Custom CSS, $30 Checkout custom fields, $35 Required user details, $40 Flat per-transaction fee, $45 Per-checkout fee override, $50 Custom domain. The money is not spent on the unlocks; it stays as your prepaid balance for fees. See the pricing page. Open →

Who pays the network (miner or gas) fee?

You do. The buyer pays the network fee on-chain, exactly as usual for your wallet and coin, and it is not part of the payment amount. The merchant's platform fee is separate and never touches your on-chain payment. The checkout shows an estimated network fee for transparency. Open →

What is a /payment/id/ link?

A /payment/id/ link is the payment page for one specific transaction, used for things like one-off payment requests, integration orders, and account top-ups. The id part is a separate encryption of the transaction reference, not a decryptable token. Opening it shows you the address screen, QR code, and countdown for that single order. Open →

If I click Pay twice, will I be charged twice?

No. Clicking a Pay button again does not by itself send anything; your wallet only moves funds when you approve a transaction in it. On the platform side, integrations can create transactions idempotently, so repeat Pay clicks for the same invoice reuse the existing pending order instead of creating duplicates. A single on-chain hash can also be credited to at most one checkout: a replay guard blocks resubmitting a known hash against a new order. Open →

What is the difference between a checkout, an invoice, and a payment request?

A checkout is a reusable payment page for a product and price, shown in a storefront or shared as a link. A payment request is a one-off link for a specific amount to a specific buyer, with no product and optionally an expiry. An invoice is the PDF tax document generated from a completed transaction, with billing details. A fourth type, the Payout Info Request, is the reverse flow used by Converters. Open →

Is the checkout available in multiple languages?

Yes. The checkout supports many languages, auto-detected from your browser, and a merchant can pin one per store. Custom translations can be added as well. See the languages docs. Open →

Can I sell digital goods with license keys?

Yes. In the Shop app a checkout can carry a pool of license keys. On a completed payment the buyer is issued a key (and/or a downloads URL), shown on the confirmation screen and emailed to them. Cancelling the transaction revokes any unclaimed key. This is a common setup for software, game codes and digital downloads. Open →

Can I pay with Bitcoin Lightning?

Yes, when the merchant has a Lightning node connected, Lightning appears as a separate method alongside on-chain Bitcoin. The platform creates a Lightning invoice, shows it as a QR code, and polls the node for settlement. Settlement is near-instant once the invoice is settled. See the Lightning docs. Open →

Can I choose which coin to pay with?

Usually yes. A checkout shows every coin the merchant has a receive address for and has marked active, and you can pick any of them. The page converts the merchant's fiat price into that coin's exact crypto amount at the live rate and takes you to the address screen. Some merchants denominate a checkout in a single crypto instead, so only that one shows. Open →

Can I have multiple stores under one account?

Yes, one account can run several stores. Each store has its own label, API key, cloud token, webhook URL and webhook secret, so separate sites or brands stay cleanly separated. You create, edit and delete stores from the dashboard, and an account with exactly one store is automatically scoped to it. Open →

Do I need to install anything or run a node to pay?

No. As a buyer you only need your own crypto wallet; there is nothing to install, and payment detection works through public explorer APIs by default. Merchants can optionally connect their own BTC node (with xpub) or Ethereum node to unlock extras like address generation, node-based refunds, and ENS resolution. Nodes are optional enhancements, never a requirement for paying. See the nodes docs. Open →

Does U.CASH Pay connect to a bank account?

No. There is no crypto-to-bank off-ramp on pay.u.cash: incoming payments settle straight to the merchant's own wallet or account. To sell crypto for a bank, card or wallet payout, use sell.u.cash; for in-person cash, a Converter can help. For accepting fiat, every checkout can offer cards through the merchant's own Stripe, PayPal or 2Checkout account plus 22 manual bank rails: ACH, X Money, Cash App, Venmo, Zelle, SWIFT, SEPA, Interac e-Transfer, Faster Payments, PayID, PIX, UPI, Alipay, WeChat Pay, PayNow, PromptPay, HK FPS, M-Pesa, TWINT, MTN MoMo (Ghana) and MoMo Vietnam, plus custom rails. Buyers pay the merchant directly, nothing is custodial, and each payment is confirmed in the console. Open →

What if I accidentally send too much?

An overpayment within tolerance is treated as a normal completion; you simply sent a bit more. The sale is credited at the expected amount and the excess stays in the merchant's receive wallet, since that is where it landed. You are not automatically refunded the difference, so contact the merchant if you want it back; they can issue a manual refund. Open →

Can I pay in several transactions or in parts?

The checkout expects a single payment of the exact amount. Sending less is treated as an underpayment (status X). If you need to pay in parts, contact the merchant and ask them to split the order into separate payment links. Sending slightly more, within tolerance, completes normally. Open →

Can a payment link stay open longer than the checkout timer?

Yes. A Payment Request link never expires by default, and the sender can optionally set an expiry of 15 minutes, 1 hour, 24 hours, 7 days, or 30 days. A live checkout you are actively paying still uses the merchant's refresh-interval timer. So a standalone request link someone sends you can stay payable for days. Open →

How are POS registers (terminals) billed?

Each account gets 1 register included free. Each additional register is a one-time $25 purchase from your credit balance, and slots are reusable: removing a register frees the slot, so a remove and re-add never double-charges. A register with an active sale cannot be removed, and existing registers are grandfathered, so nothing is ever charged retroactively. Open →

Does the checkout show a QR code I can scan?

Yes. Once you pick a coin, the address screen renders a QR code that encodes the coin URI (for example bitcoin:address?amount=... or ethereum:address?amount=...) so a mobile wallet can scan it and fill in the exact amount. A copy-address button and a deep link sit beside it. If your wallet opens with the amount pre-filled, double-check it before sending. Open →

Does U.CASH Pay screen sanctioned addresses?

Yes. Receive wallets are screened against published sanctioned-address lists, refreshed periodically, when a merchant configures them. Because the platform is non-custodial and holds no balances, the screening covers the receive side of payments. Open →

Can I integrate U.CASH Pay with Shopify?

Yes. U.CASH Pay can be wired into Shopify as a manual or alternative payment method using your store's cloud token and webhook, with webhook signing to confirm each payment. See the Shopify integration guide for the exact setup: payment provider configuration plus webhook signing. Open →

Which coins and chains can I pay with?

Built-in coins include Bitcoin (+ Lightning), Ethereum and ERC-20s, USDT and USDC across their networks, Solana, Tron, XRP, Monero, Litecoin, Bitcoin Cash, Dogecoin, TON, Algorand, Stellar, Tezos, Polkadot, Polygon, Avalanche, BNB, Arbitrum, Optimism, Base, Chainlink, BAT, and UCASH, plus newer L2s (Linea, Mantle, Berachain, Sonic, Unichain, Worldchain, Monad, Plasma, Abstract, HyperEVM, Scroll, Ink, Robinhood Chain, and Arc). Merchants can also add any custom token (ERC-20, BEP-20, Base-20, Polygon-20, Arbitrum-20, OP-20, Avax-20, TRC-20, SPL, or TON Jetton style). Card payments, where offered, run through the merchant's own card processor account. Open →

What do the order statuses mean?

Pending (P) means the order exists and is waiting for your on-chain payment. Completed (C) means the payment reached the required confirmations and the sale settled. Cancelled or expired means the order was cancelled or the timer ran out, and those rows are removed; an X status means the payment came in under the expected amount beyond the allowed tolerance. Failed or reverted EVM transactions are detected and shown as 'No payment'. Open →

What happens if I send too little?

If the amount received is less than expected beyond a small tolerance (more than a 0.1% difference), the transaction is marked underpaid (status X) rather than completed, and the checkout shows an underpayment notice. Your crypto has still arrived in the merchant's wallet, so contact them: they can refund you if a refund method is enabled, or accept the partial amount. Exact-match and within-tolerance payments complete normally. See the underpayments docs. Open →

Does U.CASH Pay handle VAT or sales tax?

Yes. With the Invoicing tier you can enable VAT/Tax at checkout. The platform calculates tax by country code, validates EU VAT numbers so B2B EU buyers can be zero-rated, and records the tax line on the transaction and the invoice. Configure rates and VAT-number validation in settings. See the VAT guide. Open →

Can I pay with MetaMask, TronLink, or Phantom?

Yes. When you have a compatible wallet extension connected, a one-tap button appears: MetaMask for EVM coins, TronLink for TRX and TRC-20, Phantom for Solana and SPL, and TON Keeper for TON. The button submits your transaction hash to the platform, which then confirms that exact on-chain transaction. That makes detection instant, even before the address scan catches it. Open →

Can U.CASH Pay use ENS, Unstoppable Domains, or FIO names instead of addresses?

Yes. Wherever a wallet address is taken (receive address setup, payout info form, payout to a payee), a human-readable name can be entered instead: ENS (*.eth), Unstoppable Domains (name.tld), or FIO (name@domain). The platform resolves the name to the on-chain address and validates the result. If a name does not resolve, the raw value you entered is used as-is. Open →

Is there a WHMCS payment gateway module?

Yes. The community WHMCS module (ucash-whmcs) lets a WHMCS store accept crypto via U.CASH Pay. Each gateway is configured per store with a cloud token and webhook secret, and a Test Connection button checks the setup before you go live. Webhooks are HMAC-signed, and invoices are marked paid only on confirmed settlement. Open →

Is there a setup fee or monthly subscription?

No. There is no setup fee, no monthly fee, no per-seat charge, and no payout fee. Merchants only pay the platform fee, a small percentage of monthly volume debited from a prepaid balance they top up whenever they like. That balance is operating funds, not a subscription. Open →

Is portal.u.cash my account or a separate product?

It is your account, not a separate product you opt into. There is one U account per email across all of U.CASH, and portal.u.cash is its home: your sign-in credentials, profile photo, name, security settings (two-factor, passkeys, trusted devices), UCASH balance, and full transaction history. A merchant account on pay.u.cash is just a U account that was given merchant powers, so the identity underneath is the same one. Open →

How does my avatar work across the U apps?

Your avatar is stored on your U account and served from portal.u.cash, so a photo you upload there shows up automatically on pay.u.cash, agents.u.cash, una.u.cash and the other apps. Until you upload one, you get your initials on a U.CASH gold circle. Your email is never part of the avatar address, so it cannot appear in an avatar URL or log. A new photo takes about 5 minutes to reach the other apps because of short-lived caching. Open →

What do I see on the dashboard after signing in?

The dashboard shows your balances (UCASH, BTC, ETH, USDT and USDC), your account status and KYC status, and how long you have been a member. Below that you get a withdrawal form for your UCASH balance, a list of any withdrawal requests you have made, and your full transaction history, paginated 25 rows per page. Each history row shows the date, description, amount, running balance and status. Open →

What is the difference between a consumer account and a merchant account?

portal.u.cash is built for you as an end user: your personal U account, balances and identity. The merchant tooling, like accepting payments, managing a store and payouts, lives on pay.u.cash. Because identity is shared through single sign-on, a merchant is just a U account that has been given merchant powers on pay.u.cash, so you never create a separate login. New merchant signup is intentionally not offered on the portal itself, which stays focused on consumers and users. Open →

If I sign out of one app, am I signed out everywhere?

Yes. Signing out of any app performs a true single logout: the app tells the portal, which ends your portal session and revokes every central session for your account across all devices and apps. It also signals each app to clear its local cookies, so no open tab can quietly sign you back in. A few self-contained apps like swap.u.cash and buy.u.cash keep no local session at all and simply follow the shared session cookie. Open →

Do I need a separate login for each U app?

No, one U account works everywhere. Sign in once on portal.u.cash and you are signed in to pay.u.cash, agents.u.cash, una.u.cash, uantum.u.cash, ai.u.cash, names.u.cash, verify.u.cash, swap.u.cash and buy.u.cash. If you start somewhere like pay.u.cash while signed out, you are sent to the portal to sign in and then returned to pay automatically. That is single sign-on: the portal vouches for you, and the other apps trust it. Open →

Why am I asked for a code again when I am already signed in?

That is step-up: an extra confirmation for sensitive actions, such as performing a payout, rotating an API key or adding a withdrawal address. If your last successful two-factor check is more than 12 hours old, the app sends you to the portal to re-enter a code or use a passkey, then brings you right back. This keeps high-risk operations protected even on a long-lived login. Accounts with no factor enrolled are not stepped up, since there is nothing to challenge. Open →

What is portal.u.cash?

portal.u.cash is your U account: the single account and identity hub for every U app. Log in once and you reach your balances and history, plus pay.u.cash, agents.u.cash, una.u.cash, uantum.u.cash, ai.u.cash, names.u.cash, verify.u.cash, swap.u.cash and buy.u.cash without re-entering your password. Your profile, avatar, two-factor settings and UCASH balance all live here, and it is also where you manage withdrawals from your portal UCASH balance. Open →

How do I close my account?

There is no self-service delete button, so to close or deactivate your account you contact support@u.cash. Your account holds your historical UCASH balance and ledger, including the migrated IBO distribution, so closure is handled manually to keep the record accurate and to deal with any open withdrawal requests. If you only want to end your sessions, signing out of any app performs a full single logout across all of them. Include your account email when you write in. Open →

What are backup codes and what if I lose them?

When you enable 2FA you get 10 single-use backup codes. Each one works once, in place of a 6-digit code, which is how you get back in if you lose your device. If you run low or lose them, go to Security and choose Regenerate backup codes: you get a fresh set and the old one stops working. Store them offline, like printed paper or a password manager, because they are displayed only when first generated. Open →

How do I change my password when I still know it?

Use the Forgot password flow even though you know your current password: go to portal.u.cash/forgot, enter your email, and follow the set-password link to choose a new password of at least 8 characters. Setting a new password immediately revokes every other session on your account, across all apps and devices, so anyone else is signed out. That makes it the recommended way to rotate your password or respond if you suspect a device is compromised. Open →

How do I create a U account?

Go to portal.u.cash/register and enter your email, a password of at least 8 characters, and optionally your first and last name. You are sent a verification email; click the link to verify your address, then sign in. New accounts start unverified and are not logged in automatically, because verifying your email first is what enables sign-in across the other apps. Once verified, the same account is already waiting for you on pay.u.cash and agents.u.cash. Open →

How do I turn off two-factor authentication or remove a device?

On the Security page, every enrolled factor has a Remove option. Removing an authenticator factor asks for your password to confirm, so a hijacked session cannot weaken your account; removing a passkey does not. You can also remove any entry from the Trusted devices list. If you remove your last factor, 2FA is effectively off for your account. Open →

Can I change the email address on my account?

Not from the profile page: your email is the identity key for your U account and for single sign-on. To change it, contact support@u.cash so the switch can be handled with re-verification of the new address, the same verify-email gate that protects sign-in everywhere. That way an attacker or a compromised session cannot silently move your account to an address you do not control. Open →

Why do I need to verify my email, and what does it unlock?

A verified email is the gate for single sign-on. When you create an account you are sent a verification link that is valid for 3 hours, and clicking it confirms you own the address and unlocks sign-in across every U app. Until then you can still sign in to the portal itself with your password, but the other apps will not accept the sign-in. You can resend the verification email from the verify-email screen, and legacy accounts imported from the original U.CASH platform already count as verified. Open →

How do I set up an authenticator app for 2FA?

Go to Security and choose Enable two-factor. Scan the QR code with your authenticator app, or enter the secret key manually, then type the 6-digit code the app shows to confirm. 2FA is now on, and you are given 10 single-use backup codes. Save them somewhere safe, like print or a password manager: each works once and they are shown only that one time. Open →

How do I reset a forgotten password?

Go to portal.u.cash/forgot and enter your email. If an active account exists for that address, a password-set link is emailed to you, valid for 3 hours; click it and choose a new password of at least 8 characters. For security the response is identical whether or not the account exists, so nobody can use this to discover which emails are registered. If your account is inactive, banned or frozen, contact support@u.cash to regain access. Open →

I am a returning U.CASH user with no password. Why am I asked to set one?

Accounts carried over from the original U.CASH platform (2015 to 2019) were imported without passwords, for security. The first time you sign in, use the Forgot password flow to set a new one, and from then on your password works normally. This forced reset only applies to imported legacy accounts; if you signed up fresh, you already chose a password at registration. Open →

Can I sign in with a passkey instead of a password?

Yes. A passkey lets you sign in with your fingerprint, face or device screen lock, with no password and no 6-digit code, and passkeys are phishing-resistant and work across every U app. Add one on the Security page with Add a passkey, then on the sign-in page choose Login with passkey. You can keep your password and 2FA as backups, and remove any passkey at any time. Open →

How do I change my name or other profile details?

Open Profile from the top-right once you are signed in. You can edit your first and last name (up to 64 characters each), upload an avatar photo, then hit Save profile. Your name and avatar are part of your U account and appear across the U apps. The email on the account is your identity key and is not changed from this page. Open →

I never got my verification email. What now?

Open the verify-email screen and use the Resend option to send a fresh link to your email. The link expires after 3 hours, so request a new one if yours has lapsed, and check your spam folder too. If you typed the wrong address when signing up, you will need to create a new account with the correct email, since verification is also what proves the address is yours. Open →

How do I get help with my account?

For anything you cannot self-serve, start a ticket at pay.u.cash/support or email support@u.cash, and include your account email. Things that need a ticket include frozen or banned accounts, email changes, closing your account, balance disputes, and non-UCASH withdrawals. For password resets, verification resends, profile and avatar edits, two-factor setup and UCASH withdrawals, use the self-service pages at portal.u.cash directly. Account questions cannot be handled over public channels because U.CASH is non-custodial. Open →

What does Trust this device for 30 days do?

When entering your 2FA code you can check Trust this device for 30 days, and on that device and browser you will skip the code at sign-in and during step-up for 30 days. The trust is bound to your browser fingerprint, so a stolen cookie will not work on a different browser. You can review and remove trusted devices any time on the Security page under Trusted devices. Open →

What is two-factor authentication and should I turn it on?

Two-factor authentication (2FA) asks for a 6-digit code from an authenticator app, such as Google Authenticator, Authy or 1Password, in addition to your password at sign-in, so someone who only has your password still cannot get in. You enable it on the Security page. Because the portal is what vouches for you across the ecosystem, turning 2FA on here protects every U app at once, not just the portal. Open →

What are the avatar upload rules?

On the Profile page, choose a JPG, PNG, WEBP or GIF file under 2 MB. The image is automatically center-cropped to a square, resized to 256x256, and saved as webp with a png fallback; the original is not kept, only the processed square. To go back to your initials, check Remove current photo and save. There is no manual crop tool, so pick a roughly square source image for best results. Open →

How do I withdraw UCASH to an external wallet?

On the dashboard, open the Withdraw section, choose a chain (Ethereum, Base or Polygon), enter the amount and your 0x receiving address, and submit. A per-chain fee is added to the amount: 500 UCASH on Ethereum, 1 on Base and 1 on Polygon. The request is created as Pending and reviewed before it is sent, and you can follow it under Your withdrawal requests on the dashboard. Withdrawals are currently UCASH only. Open →

What happens after I request a withdrawal?

Your request is recorded as Pending and the total, meaning the amount plus the chain fee, is debited from your balance immediately with a Processing transaction in your history. The team is notified to review and send it. If a request is rejected, the full total is refunded to your balance and a Completed credit row is added; once sent, completed withdrawals show the on-chain transaction hash. You can track each request under Your withdrawal requests on the dashboard. Open →

What do the account statuses active, frozen, banned and inactive mean?

Accounts can be active, inactive, frozen or banned. Only active accounts can sign in normally and request a password reset link; frozen, banned and inactive accounts cannot complete sign-in and need to contact support@u.cash to regain access. Your status is shown as a pill on the dashboard. Open →

Where does my UCASH balance and history come from?

Your balance and history come from your U account ledger. If your account was carried over from the original U.CASH platform, the balance is the running balance from your historical ledger (the authoritative last-entry value), and the history includes the 2017 to 2018 Initial Bounty Offering (IBO) token distribution plus any credits, withdrawals and transfers recorded for you. Newly earned or spent UCASH, for example AI usage charges, appends to that same ledger going forward. Open →

Does U.CASH still run bounties, and what about my old bounty tokens?

The UCASH in your balance includes tokens distributed through the original 2017 to 2018 Initial Bounty Offering (IBO), where contributors earned UCASH for helping build and promote the network. Those tokens were migrated into your U account balance at launch, so they are already part of what you see today. There is no active bounty program run from the portal; the portal describes itself as your account, wallets and bounties across every U.CASH app, with the IBO distribution forming the historical part of your balance. Open →

What does the KYC status on my dashboard mean?

Your dashboard shows whether your account is marked KYC verified or unverified, carried over from the original platform's identity records. On the consumer portal the status is informational: some activities that need stronger identity verification may prompt you for extra steps inside the relevant app, and the portal itself does not host a self-service KYC submission today. Contact support@u.cash if you believe your status is wrong. Open →

Where did the 400,000+ accounts and billions of UCASH come from?

They were migrated from the original U.CASH platform, which ran from 2015 to 2019 and held roughly 405,000 consumers with about 8.64 billion UCASH in total, including the Initial Bounty Offering distribution. Balances were computed from each account's own authoritative running ledger balance rather than a simple sum, so nothing was double-counted. The original data is preserved read-only as the source of truth, and the portal is the new active front end for those accounts. Open →

Why am I locked out after too many sign-in attempts?

Sign-in attempts are rate-limited per email and per IP, and the stricter of the two applies, to stop brute-force guessing. After 10 failed attempts the account is locked for 15 minutes, and the same throttle covers 2FA code attempts and passkey attempts. Wait for the lock to expire and try again; a successful sign-in resets the counter. Open →

What are the password requirements?

Passwords must be at least 8 characters. Yours is stored only as a one-way hash, so nobody, including U.CASH staff, can see or recover the plain password. Whenever you set or change your password, every other active session on your account is revoked, so other devices and apps are signed out until they sign in again with the new password. Open →

How are my sessions kept secure?

Session cookies are set securely by the server and marked so browser scripts cannot read them, which blocks attempts to steal a session through a compromised page. Sign-in is throttled per email and per IP, with accounts locked for 15 minutes after 10 failed attempts, and changing your password revokes all other sessions. Sign-in codes passed between apps are single-use and expire in 60 seconds, and every authentication event on your account is logged. Open →

How does signing in once work everywhere?

When you visit an app while signed out, that app sends you to portal.u.cash to authenticate. If you already have a verified portal session, the portal hands the app a single-use, short-lived code, valid for 60 seconds and usable once, which the app exchanges securely for your identity. A shared session cookie scoped across *.u.cash then keeps you signed in, so visiting another app logs you in with no new prompt. The handoff is cryptographically signed between the portal and each app, and codes cannot be replayed or reused. Open →

Which apps accept my U account sign-in?

One U account works on all of these: - pay.u.cash for payments, swap.u.cash for the exchange, buy.u.cash to buy UCASH - agents.u.cash for AI agents, una.u.cash for the Una assistant, uantum.u.cash for Uantum AI, ai.u.cash for U.CASH AI - names.u.cash for buying .u domains, and verify.u.cash The portal issues sign-in codes only for these registered apps, and it only returns you to the app you came from, so your sign-in can never be redirected to some other site. Open →

Can I withdraw BTC, ETH, USDT or USDC?

Self-service withdrawal supports UCASH only. For the BTC, ETH, USDT and USDC balances shown on your dashboard, the withdrawal form indicates these are not currently available from the self-service portal in your region or account, and support@u.cash can help you move them. This is a deliberate limitation of the consumer portal, not an error. Open →

What is the aggregator mode?

The aggregator mode is the non-custodial DEX swap, and it is the default way to trade tokens. It compares quotes across major DEXs and liquidity sources and routes your trade along the best on-chain path. On EVM chains it draws on automated market-maker pools plus request-for-quote market-maker pricing; on Solana it routes across Solana liquidity pools; between different chains it uses the bridge router. Your wallet signs the on-chain transaction directly and the swap settles against the underlying liquidity, so no intermediary ever holds your funds. Open →

What is the instant-exchange mode?

Instant mode exists for coins the non-custodial DEX cannot reach, like Bitcoin, Litecoin, XRP, TRX, and Dogecoin. It shops three regulated custodial instant-exchange services, ranks their offers by the best output amount, and lets you pick one. You send funds to a deposit address the service issues and the service pays out to your destination address. swap.u.cash acts only as an introducer and never holds your funds; the partner exchange service handles custody, payout, and KYC. Open →

Is swap.u.cash part of U.CASH?

Yes. swap.u.cash is the U.CASH exchange, one of the U.CASH product apps alongside pay.u.cash, buy.u.cash, names.u.cash, agents.u.cash, and others. It is the swap and exchange surface of the U.CASH platform, and it shares the wallet connection layer with the rest of the apps. Start swapping at swap.u.cash. Open →

What is the reserve swap?

The reserve swap is the classic U.CASH swap, still served at swap.u.cash/reserve.html. Use the mode toggle on the homepage to switch to it. The aggregator and instant-exchange modes are the primary swap paths today; the reserve swap is kept for continuity. Open →

What are the swap modes on swap.u.cash?

swap.u.cash has three modes, and you switch between them with the mode toggle on the homepage: - Aggregator: a non-custodial DEX aggregator that finds the best on-chain route for token-to-token swaps across 21 EVM chains and Solana. - Instant: an instant-exchange mode that shops three custodial exchange services to cover Bitcoin and roughly 1,500 coins the DEX rails cannot reach. - Reserve: the classic reserve swap. Open →

What is swap.u.cash?

swap.u.cash is the U.CASH exchange: a non-custodial multi-chain swap app for exchanging one cryptocurrency for another. It combines three modes: an aggregator that compares quotes across major DEXs and liquidity sources, an instant-exchange mode that shops partner exchange services for coins the DEX cannot reach, and a reserve swap. You connect your own wallet, your wallet signs every transaction, and in aggregator mode funds never leave your control. Open →

Do I have to approve a token every time I swap?

No. You approve each ERC-20 token to the shared approval contract once, and after that every swap of that token is a single signed transaction, because the per-swap authorization is an off-chain signature rather than an on-chain approval. For a brand-new token the first swap is two transactions (one approval, one swap); every later swap of the same token is one transaction. Native coin (ETH) sells are always a single transaction through the non-custodial router. The full contract list is on the Networks page. Open →

Can I swap Bitcoin on swap.u.cash?

Yes, through the instant-exchange mode. Bitcoin cannot be swapped non-custodially through EVM or Solana DEX rails, so BTC pairs go through the partner exchange services: you send BTC to a deposit address the service issues and receive your chosen coin at a destination address you control. Offers are ranked so you can pick the best rate. The aggregator itself does not handle native Bitcoin. Open →

Can the destination address be different from my connected wallet?

Yes. For cross-chain swaps the destination is decoupled from the source wallet: your source wallet signs the source-chain transaction, and you can specify any valid destination address on the destination chain. That also enables swaps between wallet families, for example swapping from an EVM wallet to a Solana address. For same-chain swaps the destination defaults to your connected wallet. Open →

How do cross-chain swaps work?

When you swap a token on one chain for a token on a different chain, swap.u.cash routes the trade through a cross-chain bridging aggregator. It picks a suitable bridge and handles the source-chain transaction plus the destination-chain payout. You sign one transaction on the source chain, and the destination coin arrives at an address you specify on the destination chain. Cross-chain swaps take longer than same-chain swaps because they wait for the bridge to finalize, so a few extra minutes is normal. Open →

Who pays gas on a swap?

You do, from your own wallet, in the native coin of the source chain: ETH (or the chain's native token) for EVM swaps, SOL for Solana swaps. swap.u.cash cannot pay gas for you because it is non-custodial and never holds your funds. Gas estimates are returned with each quote. Cross-chain swaps only need gas on the source chain; the bridge covers destination-chain costs. Open →

How does a DEX swap execute and who signs it?

In aggregator mode you connect your wallet (for example MetaMask), enter the pair and amount, and approve the swap. Your wallet signs the on-chain transaction and submits it to the network. For ERC-20 token sells, the per-swap permission is an off-chain signature, so after a one-time approval each swap is a single on-chain transaction; for native coin (ETH) sells, a non-custodial router contract wraps and swaps in one transaction. Funds move directly from your address to the destination along the on-chain route, and swap.u.cash never takes custody. Open →

How do I make a swap on swap.u.cash?

Here is the whole flow on swap.u.cash: - Choose Aggregator or Instant mode with the mode toggle. - Pick the coin you are sending and the coin you want, then enter the amount. - Connect your wallet (aggregator mode) and review the quoted rate and the 0.30% fee. - Confirm. In aggregator mode your wallet signs the on-chain transaction. In instant mode, choose an offer, enter your destination address, and send your coins to the deposit address shown. Open →

Can I use instant-exchange without a browser wallet?

Yes. The instant-exchange mode does not require a wallet extension at all. You enter the coin and amount you want to send, choose the best partner offer, and provide a destination address (and optionally a refund address). The partner exchange service issues a deposit address; you send your coins there from any wallet or exchange, and the service pays the destination coin to your address. This is how swap.u.cash covers coins and users the non-custodial DEX cannot. Open →

What is the refund address in instant-exchange for?

For non-EVM coins in instant-exchange mode (such as BTC, LTC, XRP, TRX, DOGE) you can optionally provide a refund address on the same network. If a swap fails or is underpaid and the service has to return funds, it sends them to this refund address. For EVM coins the refund reliably goes back to the sender, so the field is hidden there. It is optional but recommended for UTXO and account-model coins where a sender refund would otherwise be ambiguous. Open →

Is there a minimum amount for an instant swap?

Yes. Each partner exchange service sets a minimum amount per pair. When you enter an amount in instant-exchange mode, swap.u.cash shows and enforces the partner minimum, so if your amount is too low you will see the minimum required for that pair before you confirm. Aggregator swaps have no platform minimum; they are limited only by on-chain liquidity and gas cost. Open →

Where can I see my past swaps?

On the My Swaps page at swap.u.cash/my-swaps. Aggregator swaps are logged when they execute, and instant-exchange swaps are tracked from deposit through payout with live status. Because the DEX is non-custodial, the on-chain transaction in your own wallet is always the definitive record; My Swaps is a convenience view on top of it. Open →

Which wallets can I use with swap.u.cash?

For EVM chains, any injected EVM wallet, including MetaMask and Coinbase Wallet. For Solana, Phantom or Solflare, plus other Solana wallets via the wallet standard. The instant-exchange mode needs no wallet extension at all, since you send to a deposit address and receive at a destination address you provide. Open →

How do I find a token to swap?

Use the token search in the swap panel. Popular tokens are listed by default, and you can search by symbol or name. If a token is not listed, paste its contract address directly. Always verify the contract address against the project's official source before swapping, because anyone can deploy a token with any symbol. Open →

What is the token approval contract and why does swap.u.cash use it?

For ERC-20 sells, swap.u.cash uses a shared, industry-standard approval contract (at 0x000000000022D473030F116dDEE9F6b43AC78BA3) that lets you authorize each swap with an off-chain signature instead of a separate on-chain approval transaction. After a single one-time approval to that contract, later swaps of the same token collapse to a single signed transaction. If you have already used other major DeFi apps that rely on the same standard, you may need zero approval transactions. Native coin (ETH) sells do not use it at all; they go through the non-custodial swap router. Open →

Why might a chain route through a different aggregator?

On a few EVM chains the primary aggregation source may not cover a chain at a given moment. swap.u.cash automatically falls back to alternate same-chain routing on those chains, so you still get a quote and a working swap. The fallback is automatic and heals itself if the primary source re-enables the chain. From your perspective the swap just works; the routing happens behind the scenes. Open →

What fee does swap.u.cash charge?

A flat 0.30% fee (30 basis points) on aggregator swaps, taken from the swap output. For Solana and cross-chain swaps the fee is applied through the underlying aggregator's fee mechanism. In instant-exchange mode there is no extra markup on top of the partner rate; revenue comes from the affiliate commission paid by the partner exchange service, not an added user fee. Open →

Does instant-exchange add a markup on top of the partner rate?

No. In instant-exchange mode swap.u.cash adds zero markup to the partner's rate: the rate you see is the service's rate. swap.u.cash earns an affiliate commission from the partner rather than adding a fee on top. That is the introducer posture: the partner exchange service is the provider, and swap.u.cash ranks their offers so you get the best payout. Open →

How does swap.u.cash pick an instant-exchange service?

The instant-exchange mode shops three regulated custodial instant-exchange services. When you request an instant swap, swap.u.cash fetches a quote from each available service for your pair and ranks them by the best output amount, so you can pick the offer that pays out the most. swap.u.cash is an introducer (affiliate) for these services and never custodies funds itself. Open →

Does swap.u.cash require KYC?

The aggregator mode is non-custodial and requires no KYC, because no intermediary holds your funds. The instant-exchange mode is operated by regulated custodial exchange services which may apply KYC or AML checks depending on the pair, the amount, and your jurisdiction. swap.u.cash forwards your real IP address to the service, so KYC and geo checks apply to the actual user rather than to swap.u.cash. swap.u.cash itself is only an introducer and performs no KYC. Open →

Why are native ETH swaps only one transaction?

The underlying DEX rails spend wrapped native tokens, not raw ETH, which would normally take a wrap, an approval, and a swap: three transactions. swap.u.cash deploys a non-custodial router contract called UcashNativeRouter that wraps your ETH, approves the spender, and executes the swap in a single transaction, forwarding the output straight back to you. The router holds no funds and has no owner. Its address is listed on the Networks page. Open →

Where can I see the supported networks and contract addresses?

On the Networks and Contracts page at swap.u.cash/networks. It lists every supported network, the deployed non-custodial contract addresses (the shared approval contract used for ERC-20 sells and the UcashNativeRouter used for one-transaction native-coin sells), and which chain each contract applies to. It also documents the routing used on each chain. Think of it as the transparency page for the DEX. Open →

What does non-custodial mean for swaps?

Non-custodial means swap.u.cash never holds your cryptocurrency. In aggregator mode your own wallet signs every transaction and the trade settles directly on-chain against liquidity pools, so funds move from your address to the destination you choose without passing through any U.CASH-controlled wallet. There is no U Account that stores your balance and nothing sitting on the site to be hacked or frozen. The instant-exchange mode is different: there a custodial exchange service holds your deposit temporarily before paying out, which is why that mode is labeled separately. Details are in the swap.u.cash terms. Open →

How does swap.u.cash find the best price?

Each mode finds price its own way. Aggregator mode compares quotes across major DEXs and liquidity sources, splitting your trade across many pools and mixing in request-for-quote market-maker pricing to find the best net rate. The instant-exchange mode fetches live estimates from the three custodial services and ranks them so you can choose the highest payout. Cross-chain swaps are routed through a bridging aggregator that compares bridges. The rate displayed is the real executable quote, not an estimate. Open →

Does a swap quote expire?

Yes, and that is by design. Firm DEX quotes expire quickly, on the order of tens of seconds, because on-chain prices move constantly. For swaps that need several steps (for example wrapping ETH before swapping), swap.u.cash fetches a fresh quote immediately before you submit, so the rate you confirm reflects the market as it is right then. If a quote has expired by the time you confirm, nothing is lost: just re-run the quote and confirm the new rate. Open →

How does aggregator mode route EVM trades?

On EVM chains, aggregator mode compares quotes across major DEXs and liquidity sources, splitting your trade across pools and mixing in request-for-quote market-maker pricing, which often beats pure pool routing. the flat fee is already included in the quoted rate, so the price you see is the price you get. Your wallet executes the returned transaction data directly against the settlement contract on-chain. The routing never requires anything but your own wallet signature. Open →

What is slippage and how does swap.u.cash handle it?

Slippage is the gap between the quoted price and the price your transaction actually gets when it lands on-chain, caused by liquidity moving between quote and execution. Every swap is quoted with a minimum output amount, and if on-chain execution would return less than that minimum the transaction reverts, so you keep your funds instead of absorbing a bad fill. Each quote includes chain-specific slippage parameters tuned for that network. If a swap reverts, the only cost is the gas you spent; your tokens stay in your wallet. Open →

How do Solana swaps work on swap.u.cash?

Same-chain Solana swaps route through the Solana aggregation layer, which splits your trade across Solana liquidity pools to find the best rate. You connect a Solana wallet such as Phantom or Solflare, and your wallet signs the Solana transaction. The platform fee is applied through the aggregator's fee mechanism. Cross-chain swaps that start or end on Solana go through the bridge router instead. Open →

Which blockchains does swap.u.cash support?

The aggregator supports 21 EVM chains plus Solana. The EVM chains are Ethereum, Polygon, Arbitrum, Optimism, Base, BNB Chain, Avalanche, Linea, Scroll, Mantle, Berachain, Monad, Plasma, World Chain, Unichain, Ink, Sonic, Abstract, HyperEVM, Robinhood Chain, and Arc. Solana is supported for same-chain swaps, and cross-chain swaps between any of these networks are routed through the bridge router. The full live list is on the Networks page. Open →

How many coins can I swap?

Through the instant-exchange mode you can reach roughly 1,500 coins: Bitcoin, Ethereum, Litecoin, XRP, TRX, Dogecoin, and many more, from the merged coverage of the three custodial services. Through the aggregator you can swap any token that has liquidity on the supported EVM chains and Solana, including thousands of ERC-20 and SPL tokens. Together the two modes cover far more than either could alone. Open →

Where are the swap.u.cash terms of service?

At swap.u.cash/terms. They include the non-custodial disclaimer: swap.u.cash does not custody your funds in aggregator mode, swaps execute against on-chain contracts and bridges that carry their own risk, transactions are irreversible, and nothing on the site is financial advice. Give them a read before your first swap. Open →

Why are the aggregator and instant modes different on custody?

In aggregator mode the swap is fully non-custodial: your wallet signs on-chain and no intermediary holds funds. In instant mode the swap is service-custodial: you send coins to a deposit address issued by the partner exchange service, and that service holds the deposit and pays out your destination coin. swap.u.cash is only an introducer in instant mode and never touches the funds. The two are separated because coins like Bitcoin cannot be swapped non-custodially through EVM or Solana DEX rails. Open →

What is the difference between swap, buy, and convert?

On U.CASH, swap, buy, and convert are three related but distinct things. swap.u.cash is the general exchange: swap any token for any other token across many chains. buy.u.cash is the focused Buy UCASH page: the same engine with UCASH locked as the output, so acquiring UCASH is one step. Converters are a pay.u.cash concept: retail merchants who use pay.u.cash payment links to help customers move between cash and crypto, a human-assisted on- and off-ramp rather than a self-service DEX. To swap tokens yourself, use swap.u.cash; to buy UCASH specifically, use buy.u.cash. Open →

What is buy.u.cash?

buy.u.cash is the focused app for buying UCASH, the U.CASH network token. You pay with any token and UCASH is delivered to your wallet in one non-custodial transaction at the market price. It runs on the same engine as swap.u.cash, with UCASH locked as the output so you never have to configure the receive side yourself. Open buy.u.cash, connect a wallet, and buy. Open →

Can I buy UCASH on Ethereum and receive it on Base or Polygon in one transaction?

Yes. When you pay from Ethereum, buy.u.cash can buy UCASH and bridge it to Base or Polygon in a single transaction using a non-custodial bridge router contract. The router buys UCASH on Ethereum through the DEX, then deposits it across the canonical L1-to-L2 bridge to your address, so you get UCASH on your chosen L2 with no separate bridging step. Pick your destination (Ethereum, Base, or Polygon) in the destination selector. Open →

Who pays gas when buying UCASH?

You pay gas from your own wallet, in the native coin of the chain you pay from (ETH on Ethereum, and so on), because the buy is a non-custodial DEX swap. If your buy crosses chains, for example paying on Base to receive UCASH on Ethereum, you only pay gas on the source chain; the bridge handles destination-chain costs. The gas estimate is shown with your quote before you confirm. Open →

How does buy.u.cash work?

Connect your wallet, choose the token and chain you want to pay with, and enter an amount. buy.u.cash quotes how much UCASH you will receive at the current market rate, with UCASH locked as the output token. When you confirm, your wallet signs a single on-chain swap and UCASH is sent to your wallet. There is no separate contract to deal with and no admin-set price: the rate comes from live on-chain liquidity. Open →

What can I pay with to buy UCASH?

Anything the swap.u.cash aggregator supports: ETH, USDC, USDT, and thousands of other ERC-20 tokens across the supported EVM chains, plus SOL and SPL tokens on Solana. Pick your source token and chain, enter an amount, and the page quotes the UCASH you will receive. UCASH lands in your wallet in one transaction. Open →

Should I use buy.u.cash or swap.u.cash?

Use buy.u.cash if your goal is simply to acquire UCASH: the output is locked to UCASH, so it is a one-step buy. Use swap.u.cash if you want to swap between arbitrary tokens, compare rates, or use the instant-exchange mode for coins like Bitcoin. buy.u.cash is the simpler, focused path; swap.u.cash is the full exchange. Open →

Which wallets can I use to buy UCASH?

Any EVM wallet, such as MetaMask or Coinbase Wallet, to pay from an EVM chain, or a Solana wallet such as Phantom or Solflare when paying from Solana. buy.u.cash reuses the swap.u.cash wallet connection layer, so if a wallet works on swap.u.cash it works here. Connect from the Buy page and the rest is the same flow. Open →

What happens if I buy UCASH from a chain with no UCASH liquidity?

Nothing breaks: your buy just routes the smart way. UCASH DEX liquidity is concentrated on Ethereum, so when you pay from a chain like Base or Polygon, buy.u.cash runs a cross-chain swap: it trades your token for UCASH on Ethereum where the liquidity lives, then bridges the UCASH to your wallet on your chain. The page shows a cross-chain badge and the destination address, so you always know where the UCASH will arrive. It settles a bit slower than a same-chain buy while the bridge finalizes, and that is expected. Open →

What fee does buy.u.cash charge?

The same flat 0.30% swap fee as swap.u.cash, because buy.u.cash routes through the same DEX engine. The fee is taken from the swap output, so the UCASH amount you are quoted is what you receive. There is no separate buy fee on top. Open →

Is buy.u.cash live?

Yes, buy.u.cash is live. It routes through the swap.u.cash engine for quotes and execution. You can connect a wallet and buy UCASH at market price with any supported token right now at buy.u.cash. Open →

How is the UCASH price determined on buy.u.cash?

The price comes from live on-chain DEX liquidity, routed through the swap.u.cash engine. There is no admin-set sale price and no fixed rate: when you enter an amount you get a real executable quote for the UCASH you will receive. The 0.30% swap fee applies the same as on swap.u.cash, and because this is a market-priced DEX swap the rate moves with liquidity. Open →

Do I need to interact with a sale contract to buy UCASH?

No. There is no UCASH sale vault, claim contract, or admin-priced sale mechanism on buy.u.cash. Buying UCASH is a standard non-custodial DEX swap routed through on-chain liquidity: your wallet signs one swap transaction and UCASH is delivered to you. Earlier vault and claim-contract approaches were abandoned in favor of this simpler, market-priced model. Open →

Is buy.u.cash non-custodial?

Yes. buy.u.cash is non-custodial: your wallet signs the swap transaction and UCASH is delivered directly to your address by the on-chain liquidity route. buy.u.cash never holds your funds and there is no U.CASH custody account. It routes through the swap.u.cash DEX engine, which is itself non-custodial. Open →

What are the UCASH contract addresses?

UCASH is an ERC-20 token (8 decimals) deployed on three networks: - Ethereum: 0x92e52a1A235d9A103D970901066CE910AAceFD37 - Polygon: 0xA94880d3A4b39746E90Cdb57f8De3732c984DE14 - Base: 0x26cf750abAf38aF7109Effdbdf79bA50d2EE09A1 Always verify an address against the official source before sending funds. The full contract list is on the Networks page. Open →

Which chains can I buy UCASH on?

UCASH lives on Ethereum, Polygon, and Base. DEX liquidity for UCASH is deepest on Ethereum, so when you pay on another chain buy.u.cash automatically runs the cross-chain route and delivers UCASH on your chosen chain. When paying from Ethereum you can also bridge UCASH to Base or Polygon inside the same buy transaction using the destination selector. Open →

Why is UCASH locked as the output on buy.u.cash?

Because buy.u.cash is a dedicated Buy UCASH page. Locking UCASH as the output fixes the receive side, hides the invert button, and makes it impossible to accidentally select a different receive token. That turns the general-purpose swap engine into a one-step buy flow: pick what you pay with, confirm, and UCASH arrives. For arbitrary token-to-token swaps, use swap.u.cash instead. Open →

Is U.CASH Send non-custodial?

Yes. Send is fully non-custodial: your wallet signs one transaction per batch, and funds move straight from your wallet to your recipients through the open uDisperse contract. The contract holds nothing between calls, so there is no pooled custody and no withdrawal risk. Anyone can review the contract and its activity on any block explorer. Open →

What can I send with U.CASH Send?

You can send three kinds of assets: native coin (for example ETH on Ethereum), UCASH, or any ERC-20 token, which you select by pasting its contract address. That covers UCASH distributions, token airdrops, payroll, and multi-recipient payouts of any EVM token. Pick the network and asset first, and every recipient in the batch receives that same asset. Open →

What is U.CASH Send used for?

Use Send for any payment to many recipients at once: UCASH distributions and airdrops, token drops to community lists, payroll and contractor payouts, affiliate or bounty distributions, and refunds. Batching many transfers into one on-chain transaction saves gas and time compared to sending individually. You also keep full custody of your funds the whole way through. Open →

What is U.CASH Send?

U.CASH Send lets you mass-send UCASH, native coin, or any ERC-20 token to many recipients in one on-chain batch. Upload a CSV of address and amount pairs, preview the list, then confirm a single transaction per batch with your wallet. It is fully non-custodial: your wallet signs, and funds go directly to your recipients through the uDisperse contract, which holds nothing between calls. Open →

What is U.CASH Verify?

U.CASH Verify lets you verify your UCASH balance and associate your email address with your Ethereum wallet to unlock benefits and premium features across U.CASH and the wider Ucosystem. You sign in with your Ethereum wallet, the service reads your on-chain UCASH balance, and you submit and confirm an email. Your address is then linked to a verification level that other Ucosystem services can use to unlock perks for you. Open →

What does U.CASH Verify check?

Verify checks two things. First, your on-chain UCASH balance, read directly from the Ethereum UCASH contract (0x92e52a1A235d9A103D970901066CE910AAceFD37). Second, that you control the email address you submit, confirmed by clicking a verification link. It then links the verified email to your wallet address and assigns a level based on your holdings. Open →

Who uses U.CASH Verify?

Anyone who holds UCASH and wants to unlock benefits across U.CASH and the Ucosystem. Linking a verified email to your wallet and establishing a holdings-based level lets other Ucosystem services offer you premium access, priority support, and holder discounts without you re-proving your balance each time. The verification is reusable, so you verify once and benefit everywhere your address is recognized. Open →

What is the CSV format for U.CASH Send?

Your recipient file uses two columns, in this order: - address - the recipient's wallet address - amount - how much to send A header row is optional, and separators can be comma, tab, or semicolon, for example 0xabc...,1.5 on one line and 0xdef...,42 on the next. You can drop a .csv or .txt file onto the upload area or paste rows directly into the text box. Each batch processes up to 150 recipients. Open →

How does U.CASH Send work?

Choose your network and asset first: native coin like ETH, UCASH, or any ERC-20 token by pasting its contract address. Then upload a CSV or paste rows of recipients as address,amount (two columns, header row optional, comma, tab, or semicolon separators). Preview the parsed list, connect your wallet, and confirm one on-chain transaction for the batch. Each batch sends to up to 150 recipients. Open →

How does U.CASH Verify work?

Step 1: sign in with your Ethereum wallet to connect your address. Step 2: submit your email address. Step 3: click the verification link in the email you receive. Step 4: refresh the page to check your status. The service reads your on-chain UCASH balance, links your email to your wallet, and assigns you a level. Open →

Do I need an account to use U.CASH Verify?

No, the core flow needs no account. Connect your Ethereum wallet, and the service reads your on-chain UCASH balance and lets you link an email. Signing in with U is offered as an optional convenience on top of the wallet flow, but you can verify purely with your wallet. Open →

How many recipients can I send to at once with U.CASH Send?

Each batch sends to up to 150 recipients in a single on-chain transaction. If your list has more than 150 recipients, send multiple batches, one transaction each. Splitting into batches keeps each transaction within block gas limits while still being far cheaper and faster than sending one-by-one. Open →

Which chains does U.CASH Send support?

Send supports EVM networks including Ethereum, Polygon, Arbitrum One, OP Mainnet, Base, BNB Smart Chain, Avalanche, Linea, Scroll, Mantle, Berachain, Monad, Plasma, World Chain, Unichain, Ink, Sonic, Abstract, HyperEVM, Robinhood Chain, and Arc, with TON available as an additional network. Select your network and the asset before uploading your recipient list. Open →

Does U.CASH Verify have an API?

Yes. Verify exposes a RESTful API that other services in the Ucosystem use to check whether an address has a verified email linked to it. That check is what makes your verification reusable: you verify once with your wallet, and services can confirm your status before unlocking perks. Your holdings level is not handed out by the API; anything balance-based comes from the public chain itself. Open →

What are the U.CASH Verify levels?

Verify assigns a uLevel based on your UCASH holdings: User (Level 1, 1+ UCASH), Unifier (Level 2, 100+ UCASH), Unleasher (Level 3, 1,000+), Unrelenter (Level 4, 10,000+), Utopian (Level 5, 100,000+), and Ultimate (Level 21, 1,000,000+ UCASH). Higher levels unlock greater benefits, premium access, priority support, and discounts across the Ucosystem. Open →

Which chain does U.CASH Verify read my balance from?

Verify reads your UCASH balance from the Ethereum contract (0x92e52a1A235d9A103D970901066CE910AAceFD37), checking the balance held by your connected wallet address. Ethereum is the home chain holding the large majority of supply, so verification levels are based on your Ethereum UCASH balance. You can confirm the same balance yourself on any block explorer. Open →

Should I bridge or swap?

Bridging moves the same token from one chain to another, which is what you want when you need that exact token on a different network. Swapping exchanges one token for a different one, on the same chain or across chains. If you want the same coin on another chain, use bridge.u.cash; if you want a different coin, use swap.u.cash. Open →

What is bridge.u.cash?

bridge.u.cash moves any token between 17 blockchains, for example Ethereum to Base or Polygon to Arbitrum. It is non-custodial: your own wallet signs the transaction and U.CASH never holds your funds at any point. Open →

What is sell.u.cash?

sell.u.cash is the U.CASH app for turning crypto into cash. You can sell BTC, ETH, USDC and more and receive the payout in your bank account, to your card, or to a wallet. It is non-custodial: you send the crypto directly from your own wallet to the payout provider, and U.CASH never holds your funds. Open →

How do I bridge tokens to another chain?

Connect your wallet, choose the token, the source chain and the destination chain, and enter the amount. Review the quote and fees, then confirm in your wallet. The bridge handles the rest and the token arrives at your address on the destination chain. Open →

How does selling crypto for cash work?

Pick the coin and chain you are selling, enter the amount, and choose the fiat currency, country and payout method you want. The quote shows exactly what you will receive before you confirm. You then send the crypto from your own wallet to the address shown, and the payout is delivered to your bank, card or wallet once the transaction confirms. Open →

What is the refund address on sell.u.cash for?

The refund address is where your crypto automatically returns if a sale cannot complete, for example if a payout method becomes unavailable. It defaults to your selling wallet on the same chain, and you should always double-check it before confirming a sale. Open →

Can I sell UCASH for cash?

Yes, in two steps. First convert your UCASH to ETH, which you can do in one step at get.u.cash, then sell the ETH for your preferred fiat payout at sell.u.cash. You can also swap UCASH for any other supported coin first at swap.u.cash. Open →

Which chains does the bridge support?

The bridge covers 17 chains, including Ethereum, Base, Arbitrum, Optimism, Polygon, BNB Chain, Avalanche, zkSync, Linea, Scroll and Mantle. The app always shows the current full list when you pick a destination. Open →

What does it cost to sell crypto?

Selling costs a flat 0.50% all-in. The full amount you will receive, with the fee already applied, is shown in your quote before you confirm anything. You also pay the normal network (gas) fee for the on-chain transaction you send from your wallet. Open →

Do I need to verify my identity to sell crypto?

Identity checks and the payout itself are handled by U.CASH payment partners, who apply the verification required by the laws of your region and the payout method you choose. On the U.CASH side there is no custody: you send crypto directly from your own wallet, so there is no U.CASH account balance to verify. Open →

How can I receive my money when I sell?

Payouts go to your bank account (such as ACH or SEPA), to a card, or to wallet-based payout methods. Eight payout rails are supported in total, and availability varies by coin, fiat currency and region - the app shows you exactly which methods are available for your selection before you confirm. Open →

When is the @u handle coming?

The @u handle is coming soon: it is on the roadmap, and U.CASH Names is integrating FIO Protocol so every .u can come with a matching @u handle. There is no fixed launch date yet. Claim your .u now on names.u.cash and your matching @u will follow when the integration ships. Open →

What is the difference between a .u domain and an @u handle?

A .u domain (like yourname.u) is a blockchain domain you own as an NFT on Base, used for identity, login, decentralized websites, and crypto payments. An @u handle (like yourname@u) is a FIO Protocol name that pairs with your .u so anyone can send to you across wallets by a human-readable handle, with no address copy-pasting. The .u is live now; the @u handle is coming soon via the FIO Protocol integration. Open →

Can I use my .u to log in to Web3 apps?

Yes. Your .u works as a Web3 single sign-on: you sign in to the decentralized web in a few clicks without giving up your privacy, proving ownership by signing with the wallet that holds the name. Any app that supports .u domains for login accepts yours. Open →

How does names.u.cash fit into the U.CASH network?

names.u.cash is the identity layer of U.CASH. Your .u works with every other U.CASH app: pay to a name at U.CASH Pay, swap tokens at U.CASH Swap with your own keys, buy UCASH at U.CASH Buy, and let agents pay and get paid at U.CASH Agents. One U Account works across all of them, and the whole network lives at u.cash. Open →

What can I do with a .u name?

A .u is your identity, login, and pay address in one. Anyone can send crypto to yourname.u instead of a long address, you can log in to the decentralized web with Web3 single sign-on, you can verify your socials and show a profile page, and you can host a censorship-resistant website on IPFS pointed at your .u. It works across every U.CASH app. Open →

What is names.u.cash?

names.u.cash is the U.CASH app for claiming a Web3 identity. You search for and buy a real .u domain, issued by U.CASH's domain partner, then use it as your identity, login, and pay address across Web3. It is part of the U.CASH network alongside Pay, Swap, Buy, Agents, and Verify, and a matching @u FIO handle is on the roadmap. Open →

Where can I use my .u name?

Your .u works across the entire U.CASH network: pay to a name at U.CASH Pay, get paid, and manage your identity across all U.CASH apps with one account. Because .u is a real Web3 domain, it also works in any third-party wallet, exchange, or dApp that supports .u resolution, not just inside U.CASH. Open →

Can I buy or manage multiple .u domains at once?

Each .u is purchased individually through search, and there is no bulk-buy tool in the app today. If you sign in with your U Account, the 'My domains' view lists all the names tied to your email in one place, each with its status. For large or programmatic orders, contact U.CASH support. Open →

Can I host a website on my .u domain?

Yes. You can host a censorship-resistant site on IPFS and point your .u at it by setting the IPFS hash record on your name in your domain account with the issuer. Your content, your domain, your rules. Open →

How do I buy a .u domain?

Type the name you want into the search bar on names.u.cash and hit Search. You are taken to the issuer's checkout to check live availability and complete the purchase: it is a one-time payment and the domain is yours for life. The purchase and minting happen with the issuer, so you manage your name there after buying. Open →

How do I manage the .u domains I own?

Your .u domains are managed in your account with the issuer, where you set addresses and records. On names.u.cash, you can optionally sign in with U (your U Account) to see a 'My domains' view that lists orders linked to your email with their payment and mint status. Login is optional; the app works anonymously too. Open →

How do I check the status of my order?

Each order has a private status page at names.u.cash/order/your-order-id. The page shows your payment and mint status in near-real-time: waiting for payment, payment confirmed and minting, or your .u is live. It polls automatically, so leave the tab open after paying; the domain is live once minting completes on-chain. Open →

What wallet do I need to buy a .u?

You need an EVM-compatible wallet (Ethereum, Base, or Polygon) to mint the .u, since it is minted as an NFT on Base. Provide a standard 0x Ethereum-style address when you buy. After minting, set addresses for other chains (Bitcoin, Solana, and more) on the name so it can receive any coin. Open →

Can I pay someone using their .u name?

Yes. In any U.CASH Pay checkout, type their .u as the destination instead of a wallet address, and U.CASH resolves the name to their wallet and sends the payment there. This works anywhere U.CASH accepts an address, including payouts and payment links, and it also supports ENS (.eth) names, other Web3 domains, and FIO names. Open →

How do I set my wallet address on my .u name?

After buying your .u, open your domain account with the issuer and add the address for each coin you want to receive (Bitcoin, Ethereum, Solana, UCASH, and more) to the name's records. Once saved, anyone sending to yourname.u resolves to those addresses. When you buy through names.u.cash, your owner wallet is set automatically during minting for major coins. Open →

Do I need an account to use names.u.cash?

No. You can search and buy a .u without signing in. Logging in with your U Account is optional and adds a 'My domains' view that tracks your orders by email. Login uses U.CASH single sign-on, so one account works across names.u.cash, Pay, and the rest of the U.CASH network. Open →

Can I transfer or sell my .u domain?

Yes. The domain is an NFT in your wallet, so you can move it, sell it, or transfer it anywhere you like; transfers are done from your wallet and your domain account with the issuer, where the NFT lives. U.CASH does not lock or custody the name. Open →

Who owns the .u domain, and is it non-custodial?

You do. The domain is an NFT in your own wallet and no middleman holds it: you control it with your own keys and can move it, sell it, or transfer it any time. U.CASH never custodies your name. During minting, resolution records are set so the name points to your wallet, and you manage those records in your domain account with the issuer. Open →

How does a .u name resolve to a wallet?

U.CASH runs a name resolution engine that turns human-readable names into on-chain addresses. When you enter a name like yourname.u, the engine queries the .u resolution service for the crypto record matching the coin you are sending and returns the wallet address stored on that name. Results are cached so repeat lookups are instant, and the address is validated before the payment is sent. Open →

Is there KYC, and are there region restrictions for buying a .u?

names.u.cash itself does not require KYC to search or start a purchase; you can browse and begin buying a name anonymously. The purchase and minting complete with the .u issuer, so any identity verification, payment-method requirements, and regional restrictions that apply there govern the final transaction. Crypto payments via U.CASH Pay are non-custodial and add no KYC step on the U.CASH side. Open →

What is the difference between a .u name and a raw wallet address?

A raw wallet address is a long string of random characters (like 0xd8da6bf2...), easy to mistype and hard to remember or verify. A .u name is human-readable (yourname.u), memorable, and shareable. When you send to a .u, U.CASH resolves it to the correct underlying address for the coin you are sending, so you get the safety of the address with the convenience of a name. Open →

Which cryptocurrencies can I pay with for a .u?

The checkout supports major coins including Bitcoin, Ethereum, Tether (USDT), and UCASH; the exact list is offered at checkout and you pick one when starting a purchase. Because the final purchase completes with the .u issuer, the currencies accepted there apply to the actual mint. Open →

How much does a .u domain cost?

A .u is a one-time payment and you own it for life. Pricing is set per name by the issuer at checkout, where you see the exact price before you pay. Search your name on names.u.cash to reach the live price. Open →

How does U.CASH confirm my payment for a .u?

names.u.cash confirms your payment by checking payment status on a recurring schedule instead of depending on webhook notifications, so a failed notification never stalls your order: once the payment confirms, the domain is fulfilled. The order status page also refreshes on each view for near-real-time updates. You never need to do anything to trigger confirmation. Open →

Are there renewal fees or an expiration date?

No. You pay once and own the domain forever: there are no annual renewals and no expiration. The domain is minted as an NFT on Base and stays in your wallet for life. Open →

Does U.CASH show names instead of addresses when displaying wallets (reverse resolution)?

When a name is known for an address, U.CASH displays the human-readable name alongside it, for example on transaction details and recipient rows. Resolution is forward (name to address) for sending. Setting a primary name on an address for universal reverse display is managed through your wallet and issuer settings. Open →

Which chains does a .u resolve to?

You can set a Bitcoin, Ethereum, Solana, Polygon, Base, UCASH, and more address on a single .u name, so it resolves across the 30+ chains U.CASH supports. Each coin has its own record on the name, so sending BTC to yourname.u hits your BTC address while sending ETH hits your ETH address. Open →

What types of names can I use across U.CASH, not just .u?

U.CASH resolves three families of Web3 names anywhere an address is accepted: .u and its sister domains (like yourname.crypto), ENS names (like yourname.eth), and FIO names (like yourname@domain). Detection is based on the name's shape (.eth, name@domain, or name.tld), so new sister TLDs are picked up automatically without code changes. Open →

What is U.CASH's relationship with Unstoppable Domains?

U.CASH partnered with Unstoppable Domains to launch the .u TLD, and names.u.cash sells Unstoppable Domains-issued .u names: live availability, registration, and the final purchase all happen on the issuer's side. The .u you buy is a real Unstoppable Domain, so it works everywhere Unstoppable Domains are supported, not just within U.CASH. Open →

What are the rules for a .u name?

A .u label can be 1 to 63 characters, using lowercase letters, numbers, and hyphens. It cannot start or end with a hyphen, and uppercase is normalized to lowercase. For example, alice.u, my-name.u, and satoshi123.u are all valid. Open →

What is a .u domain?

A .u is a Web3 (blockchain) domain you own as an NFT, minted on Base. It replaces long wallet addresses with a readable name and works as your identity, login, and pay address all in one. U.CASH launched the .u TLD together with its issuing partner. Open →

What is the 402 Online Protocol (HTTP 402)?

HTTP 402 is the 'Payment Required' status code, reserved in the HTTP spec but long unused. The 402 Online Protocol turns it into a machine-to-machine payment standard: when an agent requests a priced resource, the server answers HTTP 402 with a short list of what it accepts (the asset, the seller's address, an exact amount, and an expiry), the agent pays on-chain, and the request goes through once payment is detected. No account, login, or session is needed on the buyer side. U.CASH Pay and agents.u.cash are built on it, so AI agents are first-class participants. Open →

What is U.CASH AI at ai.u.cash?

ai.u.cash is U.CASH AI, the AI app of the U.CASH network. It is the same assistant experience as Una under the U.CASH AI brand: chat to set up and manage your pay, agents and POS stores, micro-billed per action. Use whichever entry point you prefer - your setup is shared. Open →

What is the agents.u.cash x402 integration?

agents.u.cash makes AI agents first-class merchants and buyers using the unified HTTP 402 (x402) pattern across crypto and fiat. It is strictly non-custodial: every payment goes direct to the seller's own wallet, and the platform only verifies, detects on-chain, and notifies. The x402 rail is gasless USDC on Base, where the buyer signs an off-chain authorization and the platform settles it, and standard x402 clients can pay through the same resource doors. Open →

What can Una do for me?

Una sets up and manages the things you would otherwise do by hand in the dashboards: creating and adjusting stores, payment links and agent resources, and answering questions about your setup as you go. It works by chatting - you describe what you want in normal language and Una takes care of the steps. Open →

What is Una?

Una is the U.CASH AI assistant, an AI control plane for your U Apps. You chat with Una in plain language to set up and manage your pay.u.cash, agents.u.cash and pos.u.cash stores instead of hunting through settings. Una is micro-billed per action and safe by design. Open →

How does a buyer agent find what a merchant sells?

A merchant publishes a machine-readable catalog on its domain: a catalog.json file in the standard schema.org Product format that crawlers and LLMs can already read, a plain-text version, and a well-known profile describing what the merchant supports. Each listing also has its own payment door the agent can fetch directly, and hosted merchants get a shareable pay.u.cash link that works the same way. The buyer agent picks an item, pays through whichever rail it chooses (on-chain coin payment, signed USDC authorization, or card redirect), and the sale settles automatically once the payment is detected on-chain. No seller credentials are ever needed on the buyer side. Open →

How do I accept card payments?

Cards run through your own card processor account, and payments settle direct to that account, so it stays non-custodial. You connect your processor's secret key, product, and webhook secret, and the platform verifies them before saving, so a misconfiguration fails at setup rather than at checkout. Then you register the returned webhook endpoint with your processor, and buyers see a card option alongside your coin options. Open →

Can I accept a token that is not built in?

Yes. Register the token with its type (erc-20, bep-20, base-20, polygon-20, arb-20, op-20, avax-20, trc-20, arc-20, or spl, which selects the chain), a code that does not collide with a built-in coin, the contract address, decimals, and name. Then set your receive wallet for that code so buyers know where to pay. The token is auto-detected on-chain like any built-in coin, and you can list your custom tokens, remove them, and set per-token confirmation requirements at any time. Open →

How do I let AI agents pay me?

There are two ways. You can sign up directly at agents.u.cash with an email or a username, and the account is an agent from the start, working immediately at $0. Or, if you already have a pay.u.cash merchant account, open the dashboard, go to AI Agents, and click 'Link an AI agent' to flip the account in place; it auto-activates and mints an API key if none exists. Either way, you then set the wallets you want to be paid at, create your priced resources, and optionally connect a card processor for cards. Open →

How does an AI agent pay for something?

When an agent fetches a priced resource, it gets an HTTP 402 response listing one payment option per accepted asset, each with the seller's address, an exact randomized amount, and an expiry. The agent picks a rail: for coins it sends the exact amount from its own wallet to the seller's address (the platform never touches the buyer's private keys), for USDC on Base it signs an off-chain authorization that settles gasless with no buyer gas, and for cards it follows a redirect to a checkout. The platform then detects the payment on-chain and settles automatically within a few minutes, or the agent can submit the transaction hash to settle instantly instead of waiting. The challenge ID in the response is public and safe to share, because settlement still requires the real on-chain payment. Open →

How do I sign up as an agent?

Sign up at agents.u.cash with an email or just a username and a password. It is free and instant: the account works immediately at $0, with no verification and no payment required to start. Without an email you get a synthetic username@agents.u.cash address (no inbox, webhook-only). Verifying an email, when you provide one, is an optional reward that grants free starter credit up to a transaction cap plus the overseer dashboard. Open →

Can an existing merchant become an AI agent operator?

Yes, without creating a new account. From your pay.u.cash dashboard, open AI Agents and click 'Link an AI agent'; that sets the agent flag on your existing account and mints an API key if none exists. The same account then works on agents.u.cash as both a seller, paid to its own wallet, and a buyer of other agents' resources. Open →

Where do my agent earnings go?

They go straight to your own wallet (or card processor account) at the moment of payment, so there is nothing to withdraw. The platform only indexes those payments, like a block explorer, and never holds them. There is no internal withdrawable balance and no payout function; the only internal balance is your non-withdrawable fee credit, which prepays platform fees. Open →

What does non-custodial mean here?

It means every payment moves direct from buyer to seller. Coin payments land in the seller's own wallet and the platform only detects them on-chain, card payments settle to the seller's own card processor account, and signed USDC authorizations pay the seller's address while the platform only verifies them. The platform holds no user funds and no private keys, keeps no internal balance of your money, and has no withdrawal-from-balance function: it is a verifier and detector, not a custodian. Open →

Is there sanctions screening?

Yes. Sanctions screening runs at signup and whenever you set a wallet: receive addresses are checked against published sanctioned-address lists, which are refreshed periodically. A blocked address is rejected with a neutral message saying it cannot be used. The screening covers addresses used on the platform; your on-chain funds are unaffected and remain fully under your control. Open →

What payment methods can an agent accept?

Three families. On-chain coins: any address-based coin you set a wallet for, including Bitcoin, Ethereum and ERC-20s, USDT, Solana, Tron, and UCASH. Gasless USDC on Base, paid with a signed off-chain authorization (the x402-style exact rail). Cards and fiat, through your own connected card processor account. A single resource can advertise all of these at once, and the paying client chooses which rail to use. Open →

How is the platform fee charged?

The buyer always pays you the full amount, direct to your wallet. The platform fee is a small percentage that you prepay as a non-withdrawable credit balance, and it is debited separately when a sale settles, never taken from the payment itself. On the gasless USDC-on-Base rail you are also billed the relayer's gas plus a 21 percent premium per settle, and you can opt out if you would rather have buyers cover their own gas. No intermediary ever controls the transaction funds. Open →

How are refunds and underpayments handled?

Because funds move direct from buyer to seller on-chain, there is no platform-held pool to refund from. If a buyer sends less than the exact amount, the sale is reported as underpaid and does not settle, though you can choose to accept underpayments instead of requiring the exact amount. A refund, when needed, is an on-chain transfer between buyer and seller directly, like any self-custody crypto payment. The platform records what was paid and whether it matched; it cannot claw back funds it never held. Open →

How is agents.u.cash related to pay.u.cash?

An agent on agents.u.cash is a merchant on the pay.u.cash platform, and the same account, wallets, settings, and data back both. agents.u.cash is the agent-facing surface, while pay.u.cash is the underlying merchant platform. The same account also signs in to the full pay.u.cash merchant dashboard, where the 402 sales, the credit balance, and per-sale fee history are all visible. Open →

What is a resource?

A resource is a priced listing your agent sells, such as a unit of work, data, or access to something. Each one has a price and the assets you accept, and when a buyer requests it the platform mints a fresh 402 challenge with one payment entry per asset, each pointing at your own wallet with a randomized exact amount and an expiry. A resource can be coin-only, card-only, or both. Open →

Which coins and chains are supported?

Native chains include Bitcoin and Ethereum, and EVM L2s include Base, Arbitrum, Optimism, Linea, Mantle, Berachain, Sonic, Unichain, World Chain, Monad, Plasma, Abstract, Scroll, Ink, HyperEVM, Robinhood Chain, and Arc. Stablecoins include USDT on Ethereum, BSC, and Tron, USDC on Ethereum, and native USDC on Base, which powers the gasless rail. The platform token UCASH runs on Ethereum. Any other ERC-20, BEP-20, Base-20, Polygon-20, Arb-20, Op-20, Avax-20, TRC-20, or SPL token can be added as a custom token and is auto-detected on-chain just like a built-in coin. Open →

What is agents.u.cash?

agents.u.cash is a non-custodial way for AI agents, humans, and merchants to pay and get paid over plain HTTP. It makes AI agents first-class merchants on pay.u.cash, and one account is two-sided: it can sell resources and get paid straight to its own wallet, or buy resources from other agents. Every payment goes direct from buyer to seller, and the platform never holds funds or private keys. Open →

Can an AI agent pay a checkout?

Yes. On the send-payment screen, a 'Pay with your agent' button (shown when the merchant's 'Allow Agent Payments' setting is on) copies a link you hand to your AI agent. The agent fetches it, receives a 402 Online Protocol payment manifest, and pays on-chain. AI agents are first-class buyers and merchants; see agents.u.cash. Open →

How does UCASH billing work for the AI apps?

When you use an AI app like una.u.cash, uantum.u.cash or ai.u.cash, the real cost of each turn is reported to the portal, which debits UCASH from your balance. The charge is the real cost multiplied by a small per-tier markup (3x for economy models, 4x for performant models) and divided by the system UCASH price, which the portal owns so the apps themselves never handle the conversion. Charges are atomic and overdraft-safe: if your balance cannot cover a turn, the charge is refused rather than letting your balance go negative. Open →

What UCASH price is used for my AI charges?

AI usage is converted using the system UCASH price, a fixed reference rate set by the platform and currently the equivalent of $0.0021 per UCASH. The portal owns that rate and shares it with the apps so they can display equivalent values. Holding UCASH works out cheaper for AI usage than paying in credit only because of this favorable system rate, and the per-tier markup applies in both modes. Open →

Are there benefits to holding more UCASH?

Yes. U.CASH uses holding-based tiers that reduce your platform fees as your UCASH balance grows: - 1,000 UCASH: 10 percent fee discount - 10,000 UCASH: 20 percent - 50,000 UCASH: 30 percent - 100,000 UCASH: 40 percent - 210,000 UCASH: 50 percent The higher your tier, the lower the fees applied on qualifying platform activity. Open →

What is the unified balance and how does it combine my UCASH?

The unified balance is the total UCASH you can spend across U.CASH: your portal UCASH balance plus any UCASH held on the pay.u.cash side. When an AI app charges you, it draws from pay-side UCASH first and falls back to the portal balance, refunding the pay side if the portal leg then fails, so the total you see always matches what you can actually spend. You can also choose whether AI usage is billed in UCASH or in merchant fiat credit. Open →

How is Una billed?

Una is micro-billed per action, so you pay only for what you use, in tiny fractions of UCASH or from prepaid credit. There is no separate subscription for the assistant. See the AI billing entries in this FAQ for how UCASH pricing and tiers work. Open →

Do I need to hold UCASH to use U.CASH?

No. You can accept payments, swap, buy, and use names without holding a minimum balance of UCASH. Holding UCASH does unlock additional benefits: premium features, priority services, holder discounts, and use as a settlement asset for agent commerce. It is a network access and loyalty token, not a requirement to participate. Open →

What is UCASH used for?

UCASH is a network access and loyalty token. Across the Ucosystem you use it to access services, unlock premium features and discounts, pay and transact on-chain, settle machine-to-machine agent payments over HTTP-402, register and use .u and @u web3 names, and mint or use custom assets. Holding UCASH also unlocks holder discounts on domains, hosting, commerce, and services through U.ONLine and other Ucosystem properties. Open →

How is UCASH used by AI agents?

UCASH and other tokens settle machine-to-machine payments for AI agents over the HTTP-402 protocol. On U.CASH Agents, buyers pay per request and sellers earn per call. UCASH is one of the settlement assets agents use to sell priced resources and buy services autonomously, non-custodial end to end. Open →

Do UCASH holders get discounts?

Yes. Holding UCASH unlocks holder discounts on domains, hosting, commerce, and services through U.ONLine and Ucosystem properties, plus premium features and priority services across U Apps. UCASH is the network access and loyalty token, so benefits scale with participation and holdings. Open →

Why is UCASH called the network access token?

UCASH is the connective token running through every U App: pay, swap, buy, names, agents, send, and verify. It provides network access (reaching services and features), loyalty (premium benefits and discounts for holders), and a settlement asset for on-chain and agent transactions. That is what ties the whole Ucosystem together. Open →

Can I pay with UCASH?

Yes. You can use UCASH (and other assets) to pay for goods, services, and transactions across the ecosystem with fast on-chain settlement. Merchants on U.CASH Pay can accept UCASH alongside hundreds of other coins and cards in one non-custodial checkout. Open →

What is the UCASH token?

UCASH is the network access and loyalty token of the U.CASH ecosystem and the wider Ucosystem. It is a standard ERC-20 token, deployed in January 2018, used to access services, unlock premium features and discounts, pay and transact on-chain, and settle agent commerce. It is the connective token running through pay, swap, buy, names, agents, send, and verify, and it is not a security or investment. Open →

How do I earn UCASH?

UCASH is earned through real contribution, not given away. Bounties: complete tasks and claim UCASH through the u.builders bounty program, open to everyone with no job offer required. Service-usage rewards: stay active across the apps and earn through rewards and loyalty programs. You can also earn by building dApps and integrations, running a converter, or selling services and agent resources. Open →

How do I buy UCASH?

Buy UCASH at market price in one non-custodial step at buy.u.cash, the dedicated buy-UCASH flow powered by the swap engine. Alternatively, swap any asset into UCASH at swap.u.cash. Both route UCASH directly to a wallet you control. Always verify the official contract address for your chain (Ethereum, Polygon, or Base) first. Open →

How do I get UCASH?

Three ways. Buy: get UCASH at market price in one non-custodial step at buy.u.cash. Swap: swap any asset into UCASH at swap.u.cash. Earn: earn UCASH through rewards, loyalty programs, and bounties in the Portal. Always confirm you are interacting with the official contract address before buying or swapping. Open →

How do I swap another token for UCASH?

Swap any asset into UCASH at swap.u.cash, a non-custodial aggregator with a flat 0.30% fee. Your wallet signs every swap, so funds settle on-chain to addresses you control. Select UCASH as the output token on your chain (Ethereum, Polygon, or Base) and confirm the official contract if prompted. Open →

Where do I store UCASH?

Store UCASH in any compatible ERC-20 wallet on Ethereum, Polygon, or Base. Because it is a standard ERC-20, it works with MetaMask, hardware wallets, and any wallet that supports custom ERC-20 tokens. For Polygon or Base UCASH, add the corresponding contract address to your wallet to make the balance visible. Open →

Where can I verify UCASH holdings?

You can verify UCASH holdings on any public block explorer using the official contract addresses: Ethereum 0x92e52a1A235d9A103D970901066CE910AAceFD37, Polygon 0xA94880d3A4b39746E90Cdb57f8De3732c984DE14, and Base 0x26cf750abAf38aF7109Effdbdf79bA50d2EE09A1. The labeled top holdings on Ethereum are listed on the U.CASH economy page. The full holder list is public record on-chain. Open →

What is the UCASH Base contract address?

On Base, the UCASH contract is 0x26cf750abAf38aF7109Effdbdf79bA50d2EE09A1. You can verify it on any block explorer that covers Base. Base holds about 2.4% of supply, custodied by the Base bridge contract on Ethereum. Open →

What are the UCASH bounty offerings?

About 42% of UCASH supply sits in five labeled bounty-offering reserves that fund ecosystem work. They are FBO (Future Bounty Offering, ~15.45%), OBO (Ongoing Bounty Offering, ~13.41%), BBO (Build Bounty Offering, ~8.65%), PBO (Partner Bounty Offering, ~3.65%), and LBO (Liquidity Bounty Offering, ~0.89%). Some balance in these accounts is held on behalf of legacy portal users who have not yet withdrawn their original UCASH; only the share earmarked for future ecosystem work counts as not circulating, roughly a third of total supply. They pay out through the u.builders bounty program. Open →

Which blockchains is UCASH on?

UCASH is an ERC-20 on three chains: Ethereum, Polygon, and Base. Each has its own contract address. Ethereum is the home chain holding the large majority of supply, while the Polygon and Base bridge contracts on Ethereum custody the cross-chain supply. Always verify the address for the specific chain before interacting. Open →

How much UCASH is in circulation?

About 14 billion UCASH (14B+) is in circulation, approximately 66.7% of the 21B max cap. The remaining roughly 33.3% (about 7B) is reserved to the cap. The portion earmarked for future ecosystem work in the bounty reserves counts as not yet circulating. Open →

What are the official UCASH contract addresses?

UCASH is an ERC-20 on three chains. Ethereum: 0x92e52a1A235d9A103D970901066CE910AAceFD37. Polygon: 0xA94880d3A4b39746E90Cdb57f8De3732c984DE14. Base: 0x26cf750abAf38aF7109Effdbdf79bA50d2EE09A1. Always verify the contract address before interacting, since fake tokens with similar names exist. Open →

How is UCASH distributed across chains?

Most UCASH stays on Ethereum, the home chain: about 94.9% of supply. Polygon holds about 2.7% and Base about 2.4%, with both cross-chain portions custodied by their respective bridge contracts on Ethereum. The bridge contracts hold the bridged supply, so the cross-chain tokens are fully backed on the home chain, and you can verify the custody addresses on any block explorer. Open →

When was UCASH launched?

The UCASH ERC-20 token was deployed in January 2018 as the network access and loyalty token for the U.CASH ecosystem. The U.CASH project itself has been active since 2015. Open →

What is the UCASH Ethereum contract address?

On Ethereum (ERC-20), the UCASH contract is 0x92e52a1A235d9A103D970901066CE910AAceFD37. You can verify it on any block explorer that covers Ethereum. Ethereum is the home chain and holds about 94.9% of the total UCASH supply. Open →

How many UCASH holders are there?

There are 318,000+ (318K+) on-chain UCASH holders spread across more than 318K wallets, alongside over 1 million (1M+) lifetime signups on the U.CASH network. The largest holdings are not private allocations but labeled network functions such as bounty reserves, bridge contracts, exchange wallets, and liquidity venues. Open →

Who holds the most UCASH?

The largest UCASH holdings on Ethereum are not private allocations but labeled network functions. The top labels are the bounty-offering reserves: FBO (Future Bounty Offering, ~15.45%), OBO (Ongoing Bounty Offering, ~13.41%), and BBO (Build Bounty Offering, ~8.65%), followed by exchange wallets such as Yobit (~4.41%) and C2CX (~3.95%), then PBO (Partner Bounty Offering, ~3.65%), the Polygon and Base bridge contracts, a liquidity pool, and operational accounts. The remainder is spread across 318K+ wallets, and each address is public and viewable on any block explorer. Open →

Is UCASH an investment or security?

No. UCASH is explicitly described as a network access and loyalty token, not a security or investment. Its purpose is to access services, unlock premium features and discounts, pay, transact, and settle agent commerce across the U.CASH network. As with any token, always do your own research. Open →

What is the UCASH Polygon contract address?

On Polygon, the UCASH contract is 0xA94880d3A4b39746E90Cdb57f8De3732c984DE14. You can verify it on any block explorer that covers Polygon. Polygon holds about 2.7% of supply, custodied by the Polygon bridge contract on Ethereum. Open →

What token standard is UCASH?

UCASH is a standard ERC-20 token. It is deployed on Ethereum (the home chain) and bridged to Polygon and Base, each as an ERC-20 with its own contract address. You can store it in any compatible ERC-20 wallet on Ethereum, Polygon, or Base. Open →

What is the UCASH total supply?

UCASH has a fixed maximum cap of 21 billion (21B) tokens. About 14 billion (14B+) is in circulation, roughly 66.7% of the cap, leaving around 7B remaining to the 21B cap. The 21 billion max cap is hard and does not increase. Open →

How do I authenticate API requests?

Send the api_key you receive at signup in the X-Api-Key header on seller-side requests. Buyer-side surfaces are public and need no key: the resource door, payment verification, and the discovery catalogs. You can rotate your key from the dashboard, and SDKs are listed in the developer hub. Open →

How do I get notified when a sale settles?

Set a webhook URL and signing secret in your settings. When a sale settles, the platform POSTs to that URL with an HMAC signature you verify against your secret, and you can rotate the secret anytime. Email notices for sales and underpayments also work out of the box, defaulting to your signup email. Open →

Where is the developer hub, and what is in it?

The developer hub is at u.cash/developers. It covers the universal embed, the REST API with signed webhooks, SDKs across 12 language registries, the MCP server for agent runtimes, and the open standards (HTTP 402 and UCP). There is a quick start with three paths: drop in the embed script, call the API server-side, or verify a webhook. The full API and webhook reference for U.CASH Pay lives at pay.u.cash/docs. Open →

What is the fastest way to integrate U.CASH payments?

The fastest path is the universal embed: add a script tag pointing at pay.u.cash/embed.js with your publishable store cloud token (data-cloud="st_..."), an amount, and a currency. No server is needed, and the token is browser-safe. For server-side control, call the create-transaction endpoint from the server-side API, your cloud token, amount, currency, and an external_reference; the request is idempotent per external_reference. You get back a payment link to redirect the buyer to. Open →

If my store cloud token leaks, can I rotate it?

Yes. Store cloud tokens are opaque and rotation-proof: rotating a store's token immediately invalidates the old one without breaking payment links you have already issued, because links reference the store by a stable internal id. Rotate the token from the dashboard, then re-copy the new one once into your integrations. Open →

Is there an MCP server?

Yes. A stdio MCP server lets an AI agent drive a seller account as tools: set wallets and webhooks, create and list resources, read settlements, manage settings, cards, and custom tokens, and push-verify a payment from the buyer side. The server package is published on PyPI, you configure it with your API key and base URL, and it runs locally rather than being served over HTTP. See the developer hub for details. Open →

Where is the full API reference for U.CASH Pay?

The full API, webhook, and SDK reference for U.CASH Pay lives at pay.u.cash/docs. It covers the create-transaction and create-checkout endpoints, the test-connection endpoint for validating a webhook URL, the X-Webhook-Signature signing contract, and per-store credentials. The developer hub at u.cash/developers summarizes the same contract with quick-start examples. Open →

Which SDKs and libraries does U.CASH offer?

U.CASH ships zero-dependency SDKs across 12 language registries: JavaScript/TypeScript (including React, Vue, Svelte, Solid, Preact, Angular, Next, Nuxt, Astro, and Deno), Python, Rust, Java, .NET, Elixir, Deno, Flutter/Dart, Ruby, PHP (Laravel and Symfony), Swift, and Go. All of them share the same createCheckout and verifyWebhook contract. Some are live on their public package registries and others are build-ready in the open repositories; see u.cash/developers for the current list. Open →

How do U.CASH webhooks work and how do I verify them?

When a payment is confirmed, U.CASH Pay sends an HTTP POST to your webhook URL with an X-Webhook-Signature header of the form t=<unix-seconds>,v1=<hex>. The v1 value is an HMAC-SHA256 over the timestamp, a period, and the raw request body, keyed with your webhook secret. To verify: parse t and v1, reject anything older than 300 seconds (replay protection), recompute the HMAC over the raw body, and compare in constant time. Use the event_id field to deduplicate, since the same confirmed transaction may be delivered more than once. Always hash the exact bytes you received, because re-encoding the JSON breaks the signature. Open →

What is the difference between the cloud token and the API key?

Your cloud token (it starts with st_) is publishable and safe to put in buyer-facing URLs and embeds; it identifies your store to the checkout. Your API key is a secret server-side credential for the REST API and must never be exposed in the browser. The checkout only ever reads the cloud token; the API key is used server-to-server. Open →

What is fees.u.cash?

fees.u.cash is a live, read-only index of pump.fun creator fees on Solana. Many pump.fun tokens route their creator fees to a payout address (a "sharing config"). fees.u.cash tracks those tokens, every fee claim, and leaderboards by attributed creator - all straight from on-chain data, updated continuously, with a public API. It is an independent data surface: U.CASH is not affiliated with pump.fun or any fee-routing service. Token metadata lines are reproduced verbatim; attribution reflects only what token publishers wrote on-chain. The site also carries a self-custody fee wizard: route a coin's fees to your own wallet, sweep unclaimed vaults, or launch a new coin - every transaction is signed by you in your browser, and U.CASH never holds funds. See How do I receive my pump.fun creator fees? for the walkthrough. Open →

How do I receive my pump.fun creator fees?

When a pump.fun token routes its creator fees, they accrue in an on-chain vault and pay out to the addresses in its sharing config. To receive yours, open the fee wizard at fees.u.cash and connect your wallet (Phantom, Solflare, or Backpack). Paste your coin's mint address, set the receive address - it can be any Solana address, including your pay.u.cash receive address - and approve the transactions your wallet presents (two for a coin routing fees for the first time: creating the sharing config, then setting your payout). Your wallet signs everything; U.CASH never holds or touches the funds. Three on-chain rules shape what happens next: Routing is one-shot. The first fee-share update sets the payout split and revokes further changes on-chain. Pick the receive address carefully; it cannot be re-routed afterwards. Fees accrue, then pay out on a sweep. Creator fees collect in the token's fee vault. Once the balance clears a small on-chain minimum (about 0.0007 SOL, covering account rent and per-recipient costs), anyone can sweep it - usually you, with one click from the token's page at fees.u.cash. Sweeping is permissionless: whoever triggers it pays only their own transaction fee, and the funds go only to the configured receive addresses. The fee rate is set by the protocol. For SOL-quoted pump.fun coins the creator fee percentage is fixed on-chain; the wizard routes where fees go, not how much they are. To catch accruals without checking manually, create a vault alert on notify.u.cash and get an email when unclaimed fees cross your threshold. The same wizard can also launch a brand-new coin with fees pre-routed to your address. Open →