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Operational

One-Time Purchase Integration - Stellar BYO Wallet Settlement

This page is for advanced / cryptocurrency-native companies. If that’s not you, head back to the Quickstart for the standard flows.

This guide walks you through integrating Coinflow checkout to accept one-time credit card purchases with USDC settlement on the Stellar network — without requiring a smart contract. USDC is sent directly to your configured settlement wallet.

Prerequisites

Complete these steps before starting the integration.

Create your sandbox account

Register or login to your sandbox merchant account

Generate API keys

Create a sandbox API key for authentication

Add chargeback protection

Add the protection script to every page of your app

Configure settlement

Set up your BYO Wallet — your own Stellar wallet with a USDC trustline to receive USDC revenue.

USDC transfers to a BYO wallet do not require a stellarTransaction. No smart contract whitelisting or transaction construction is needed.

Stellar checkout does not support Credits settlement or partial purchases where the customer contributes their own USDC alongside a credit card payment.

Quick Reference

Authorization Headers

Header Description
Authorization Your API key from the merchant dashboard
x-coinflow-auth-user-id Unique customer ID from your system
x-coinflow-auth-blockchain Use stellar for Stellar settlement
x-coinflow-auth-session-key JWT token authorizing the payer (valid 24 hours)

Helpful Resources

Choose Your Implementation

Best for simple integrations. Generate a hosted checkout URL to redirect users or embed in an iframe.

curl -X POST https://api-sandbox.coinflow.cash/api/checkout/link \
  -H "x-coinflow-auth-user-id: customer123" \
  -H "x-coinflow-auth-blockchain: stellar" \
  -H "Authorization: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "email": "customer@example.com",
    "subtotal": {
      "cents": 500,
      "currency": "USD"
    },
    "blockchain": "stellar",
    "settlementType": "USDC",
    "chargebackProtectionData": [{
      "productType": "inGameProduct",
      "productName": "Digital Item",
      "quantity": 1,
      "rawProductData": {
        "description": "A digital purchase"
      }
    }],
    "deviceId": "123456789"
  }'
{
  "link": "https://sandbox.coinflow.cash/stellar/purchase-v2/YOUR_MERCHANT_ID?sessionKey=eyJhbGci..."
}

Embed in an iframe

<iframe
  allow="payment"
  src="CHECKOUT_LINK_FROM_STEP_1"
  style="width: 100%; height: 600px; border: none;"
/>

Step 3: Handle success events

Listen for payment completion when using an iframe:

window.addEventListener('message', (event) => {
  if (typeof event.data === 'string') {
    const data = JSON.parse(event.data);
    if (data.data === 'success') {
      console.log('Payment ID:', data.info.paymentId);
    }
  }
});

React SDK

Best for React applications. Provides a pre-built checkout component.

Step 1: Install the SDK

npm install @coinflowlabs/react

Step 2: Tokenize checkout parameters

Encrypt checkout parameters from your backend to prevent tampering.

curl --request POST \
     --url https://api-sandbox.coinflow.cash/api/checkout/jwt-token \
     --header 'Authorization: YOUR_API_KEY' \
     --header 'accept: application/json' \
     --header 'content-type: application/json' \
     --data '{
       "subtotal": {
         "currency": "USD",
         "cents": 500
       },
       "email": "customer@example.com",
       "blockchain": "stellar",
       "settlementType": "USDC",
       "chargebackProtectionData": [{
         "productType": "inGameProduct",
         "productName": "Digital Item",
         "quantity": 1,
         "rawProductData": {
           "description": "A digital purchase"
         }
       }],
       "deviceId": "123456789"
     }'
{
  "checkoutJwtToken": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9..."
}

Step 3: Render the checkout component

import { CoinflowPurchase } from '@coinflowlabs/react';

function Checkout() {
  const stellarWallet = {
    address: "GBCG42WTVWPO4Q6OZCYI3D6ZSTFMO6S2WPUFM3MYO7LEDFCZU3IDALU",
    sendTransaction: async (base64Xdr: string) => "tx_hash",
    signTransaction: async (base64Xdr: string) => "signed_xdr",
    signMessage: async (message: string) => "signature",
  };

  return (
    <CoinflowPurchase
      wallet={stellarWallet}
      merchantId="your-merchant-id"
      env="sandbox"
      blockchain="stellar"
      jwtToken="JWT_TOKEN_FROM_STEP_2"
      subtotal={{ cents: 500, currency: 'USD' }}
      onSuccess={(paymentId) => {
        console.log('Payment successful:', paymentId);
      }}
    />
  );
}

For direct USDC transfers, do not pass a transaction prop. Omitting it tells Coinflow to settle directly to your configured wallet.

Step 4: Configure your dashboard

  1. Customize the UI to match your brand from your dashboard
  2. Whitelist your domain to prevent unauthorized embedding

API Only

Best for custom checkout UIs. Full control over the payment flow.

Step 1: Get a session key

curl --request GET \
     --url https://api-sandbox.coinflow.cash/api/auth/session-key \
     --header 'Authorization: YOUR_API_KEY' \
     --header 'accept: application/json' \
     --header 'x-coinflow-auth-user-id: customer123'
{
  "key": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9..."
}

Step 2: Get pricing totals

curl --request POST \
     --url https://api-sandbox.coinflow.cash/api/checkout/totals/YOUR_MERCHANT_ID \
     --header 'accept: application/json' \
     --header 'content-type: application/json' \
     --header 'x-coinflow-auth-session-key: SESSION_KEY_FROM_STEP_1' \
     --data '{
       "subtotal": { "cents": 500 },
       "settlementType": "USDC"
     }'
{
  "card": {
    "subtotal": { "cents": 500 },
    "creditCardFees": { "cents": 40 },
    "chargebackProtectionFees": { "cents": 0 },
    "gasFees": { "cents": 0 },
    "total": { "cents": 540 }
  }
}

Step 3: Tokenize the credit card

See PCI-compliant card tokenization for implementation details.

Step 4: Tokenize checkout parameters

curl --request POST \
     --url https://api-sandbox.coinflow.cash/api/checkout/jwt-token \
     --header 'Authorization: YOUR_API_KEY' \
     --header 'accept: application/json' \
     --header 'content-type: application/json' \
     --data '{
       "subtotal": { "currency": "USD", "cents": 500 },
       "email": "customer@example.com",
       "blockchain": "stellar",
       "settlementType": "USDC",
       "chargebackProtectionData": [{
         "productName": "Digital Item",
         "quantity": 1,
         "productType": "inGameProduct",
         "rawProductData": {
           "description": "A digital purchase"
         }
       }],
       "deviceId": "123456789"
     }'
{
  "checkoutJwtToken": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9..."
}

Step 5: Process the payment

curl --request POST \
     --url https://api-sandbox.coinflow.cash/api/checkout/card/YOUR_MERCHANT_ID \
     --header 'accept: application/json' \
     --header 'content-type: application/json' \
     --header 'x-coinflow-auth-session-key: SESSION_KEY' \
     --header 'x-coinflow-client-ip: CUSTOMER_IP_ADDRESS' \
     --header 'x-device-id: DEVICE_ID_FROM_PROTECTION_SCRIPT' \
     --header 'user-agent: CUSTOMER_USER_AGENT' \
     --data '{
       "subtotal": { "currency": "USD", "cents": 500 },
       "jwtToken": "JWT_TOKEN_FROM_STEP_4",
       "card": {
         "cardToken": "TOKENIZED_CARD_FROM_STEP_3",
         "expYear": "30",
         "expMonth": "10",
         "email": "customer@example.com",
         "firstName": "John",
         "lastName": "Doe",
         "address1": "123 Main St",
         "city": "New York",
         "zip": "10001",
         "state": "NY",
         "country": "US"
       }
     }'
{
  "paymentId": "f3fc8a34-680b-4b91-905b-1db5628bbb0e"
}

For saved cards:

Re-tokenize the saved card with CVV first (see card tokenization docs), then:

curl --request POST \
     --url https://api-sandbox.coinflow.cash/api/checkout/token/YOUR_MERCHANT_ID \
     --header 'accept: application/json' \
     --header 'content-type: application/json' \
     --header 'x-coinflow-auth-session-key: SESSION_KEY' \
     --header 'x-coinflow-client-ip: CUSTOMER_IP_ADDRESS' \
     --header 'x-device-id: DEVICE_ID' \
     --data '{
       "subtotal": { "currency": "USD", "cents": 500 },
       "jwtToken": "JWT_TOKEN_FROM_STEP_4",
       "token": "REFRESHED_CARD_TOKEN"
     }'
{
  "paymentId": "0090c04b-1ae8-4672-a108-32874df36f11"
}

Step 6: Verify the payment (optional)

curl --request GET \
     --url https://api-sandbox.coinflow.cash/api/merchant/payments/enhanced/PAYMENT_ID \
     --header 'Authorization: YOUR_API_KEY' \
     --header 'accept: application/json'

3DS Authentication

After implementing basic checkout, add 3DS for stronger authentication. Contact Coinflow to enable 3DS on your account.

Complete Checkout with 3DS Challenge

Learn how to add 3DS to your new card and saved card requests

Chargeback Protection

Improve approval rates and reduce fraud by sharing payer events with Coinflow.

Send user events

Track key user actions throughout their journey on your app.

curl --request POST \
     --url https://api-sandbox.coinflow.cash/api/events \
     --header 'Authorization: YOUR_API_KEY' \
     --header 'content-type: application/json' \
     --data '{
       "eventType": "SignUp",
       "customerId": "user-123-abc",
       "country": "US",
       "username": "johndoe",
       "email": "john@example.com",
       "firstName": "John",
       "lastName": "Doe"
     }'
curl --request POST \
     --url https://api-sandbox.coinflow.cash/api/events \
     --header 'Authorization: YOUR_API_KEY' \
     --header 'content-type: application/json' \
     --data '{
       "eventType": "SignIn",
       "customerId": "user-123-abc",
       "country": "US",
       "email": "john@example.com"
     }'

Required headers for checkout

When processing payments, include these headers for chargeback protection:

Header Description
x-device-id Device ID from the chargeback protection script
x-coinflow-client-ip Customer’s IPv4 address
user-agent Customer’s browser user agent

On sandbox, use the test partnerId provided by the Coinflow team when configuring the protection script.

Next Steps

Test Your Integration

Use sandbox test cards to verify your implementation

Configure Webhooks

Receive real-time payment notifications

Go Live

Create your production merchant account

API Reference

Explore the complete API documentation