Card Developer

UC Card Open Platform

Accept USDT payments from millions of UC Card users

Add Sign in with UC Card and in-app USDT checkout to your website or app. Create a payment on your server, the user confirms it in the UC Card App, and you get a signed callback.

Get started API reference

One signed request to get paid

const payment = await htp('POST', '/open/v1/payments', {
  out_order_no: 'A20261107-0001',
  amount: '40.00',
  currency: 'USDT',
  description: 'Premium membership',
  payer_sub: user.htpSub,
}, idempotencyKey);

// Show payment.checkout_url to the user
// → they confirm in the UC Card App
// → you receive a signed "payment.paid" callback

What you can build

Sign in with UC Card

Let anyone with a UC Card account log in to your UC Card Partner website or app with one tap. Standard OpenID Connect with PKCE. Use it alone or with payments.

Online payments

Create a payment, send users to the UC Card cashier, and receive payment.paid when they confirm with their PIN.

Refunds

Refund all or part of a payment instantly from your developer wallet.

Payouts

Send USDT rewards, winnings or settlements to UC Card users with one call.

How a payment works

UC Card PartnerUC CardUser · UC Card AppCheckoutOrder on your siteCreate paymentPOST /open/v1/paymentsOpen cashierSend user to checkout_urlConfirm with PINIn the UC Card AppSend callbackpayment.paid · signedPaid · 2xxVerify, mark order paidSigned requestcheckout_urlOpen in appPaidPOST callback

Go live in five steps

  1. 1

    Register as a developer

    Sign in to the console with your verified UC Card account and create an app.

  2. 2

    Apply for payments

    Tell us about your business. We approve limits and fees.

  3. 3

    Get sandbox keys

    Create an ok_test_ API key and set your callback URL.

  4. 4

    Integrate & test

    Sign requests, create payments, verify callbacks with test users.

  5. 5

    Go live

    Publish your app, switch to an ok_live_ key, reconcile daily.

Developer tools

Sign-in button

Generate a "Continue with UC Card" button for your login page and copy the HTML and CSS.

Signature generator

Build string_to_sign and X-Signature for any request, and copy a ready curl command.

Callback verifier

Paste a callback you received and check its signature and timestamp.

OpenAPI spec

Download the OpenAPI 3.1 file. Import it into Postman, Insomnia or a code generator.

Ready to integrate?

Open the developer console to create your app and sandbox API keys.

Log in to Console