Stablecoin payment API: integrate in an afternoon

The flow

1. Create a payment from your server.
2. Redirect the customer to checkout_url, or show address and amount_due in your own UI.
3. Fulfil on webhook: mark the order paid when payment.paid arrives.

1. Create a payment

curl https://wolf-pay-five.vercel.app/api/v1/payments \
  -H "Authorization: Bearer $WOLF_PAY_SECRET_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: order_1001" \
  -d '{"amount": "25.50", "currency": "USDT", "network": "tron", "order_id": "1001", "redirect_url": "https://yourstore.com/thanks"}'

Amounts are decimal strings so nothing is lost to floating-point rounding. Retrying with the same Idempotency-Key returns the original payment instead of creating a second one.

2. Send the customer to the checkout

The response includes checkout_url: a mobile-friendly page with the amount, QR code, address, network, countdown and live status. After a successful payment the customer is sent back to your redirect_url.

3. Verify the webhook and fulfil

Each event is signed in the Wolf-Signature header (t=…,v1=…), where v1 is the HMAC-SHA256 of <t>.<raw body> with your endpoint's secret.

import { createHmac, timingSafeEqual } from "node:crypto";

export function verifyWolfPay(rawBody: string, header: string, secret: string) {
  const parts = Object.fromEntries(header.split(",").map((p) => p.split("=")));
  const age = Math.abs(Date.now() / 1000 - Number(parts.t));
  if (!parts.t || !parts.v1 || age > 300) return false;
  const expected = createHmac("sha256", secret).update(`${parts.t}.${rawBody}`).digest("hex");
  return expected.length === parts.v1.length && timingSafeEqual(Buffer.from(expected), Buffer.from(parts.v1));
}

Answer with a 2xx within 10 seconds. Failed deliveries are retried 8 times over about 28 hours; use Wolf-Event-Id to skip duplicates.

Events

Test mode

wp_test_… keys create test payments. The checkout shows buttons to simulate paying in full, too little, too much, or letting the payment expire, and they trigger the same webhooks live payments do.

Also available

• Refunds: POST /refunds sends money back to the address that paid.
• Balance and payouts: read your balance and payouts; payouts are created in the dashboard only.
• A Node.js SDK (@wolfpay/node), typed, with retries and idempotency built in. It's being published to npm; until then the REST API works from any language.

Full reference: API docs.