Accept USDT with a single API call.

Overview

The flow is the same for every integration:

1. Your server calls POST /deposit/initiate and gets back a unique Solana address and a hosted page_url.
2. You send the customer to page_url (or show the address / QR yourself).
3. The customer sends USDT. We confirm it on-chain and call your webhook.
4. You mark the order paid. Funds settle to your wallet.

Base URL: https://api.hexpaid.com · All requests and responses are JSON over HTTPS.

Authentication

Sign up, then copy your API key from Dashboard → Developers. Send it in the X-API-Key header from your server — never from browser code.

X-API-Key: merch_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Create a payment

POST /merchants/solana/deposit/initiate reserves a Solana address for 10 minutes and starts monitoring it.

curl -X POST https://api.hexpaid.com/merchants/solana/deposit/initiate \
  -H "X-API-Key: $HEXPAY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "expected_amount": 25,
    "order_id": "ORD-1042"
  }'

{
  "deposit_id": 128,
  "status": "pending",
  "message": "Deposit initiated. Share the page URL with your customer.",
  "page_url": "https://api.swapuzi.com/merchants/solana/deposit/128/page",
  "address": "7xKXtg2CW87d97TXJSDpbD5jBkheTqA83TZRuJosgAsU",
  "order_id": "ORD-1042",
  "expires_at": "2026-10-08T12:10:00Z",
  "created_at": "2026-10-08T12:00:00Z"
}

Payment lifecycle

When an expected_amount is set, webhooks also carry payment_status: paid (exact), partial (less — keep waiting or top up) or overpaid (more — refund the difference if you wish).

Retrieve & list payments

Poll GET /merchants/solana/deposit/:id as a fallback to webhooks, or list payments with GET /merchants/solana/deposits (filters: status, limit ≤ 200, before_id for paging).

curl https://api.hexpaid.com/merchants/solana/deposit/128 \
  -H "X-API-Key: $HEXPAY_API_KEY"

Webhooks

Set an account-wide URL in Dashboard → Developers, or pass webhook_url per payment. URLs must be public https endpoints. Return any 2xx within 10 seconds to acknowledge; otherwise we retry after 5 s, 30 s and 2 min (4 attempts total). Every attempt appears in your delivery log.

{
  "event": "deposit.confirmed",
  "merchant_id": 42,
  "deposit_id": 128,
  "order_id": "ORD-1042",
  "tx_id": "5VqK…Zk",
  "solana_address": "7xKXtg2CW87d97TXJSDpbD5jBkheTqA83TZRuJosgAsU",
  "amount": 25,
  "received_amount": 25,
  "expected_amount": 25,
  "payment_status": "paid",
  "status": "confirmed",
  "asset": "USDT",
  "timestamp": 1791460800
}

Webhooks may arrive more than once or out of order. Make your handler idempotent on deposit_id / X-HexPay-Delivery.

Verify signatures

Always verify the signature against the raw request body, compare in constant time, and reject timestamps older than five minutes to block replays.

import crypto from "node:crypto";

app.post("/webhooks/sonrails", express.raw({ type: "application/json" }), (req, res) => {
  const ts  = req.get("X-HexPay-Timestamp");
  const sig = req.get("X-HexPay-Signature");
  const expected = crypto.createHmac("sha256", process.env.HEXPAY_WEBHOOK_SECRET)
    .update(ts + "." + req.body).digest("hex");

  const valid = sig && sig.length === expected.length &&
    crypto.timingSafeEqual(Buffer.from(sig), Buffer.from(expected));
  if (!valid || Math.abs(Date.now() / 1000 - Number(ts)) > 300) return res.sendStatus(401);

  const event = JSON.parse(req.body);
  if (event.event === "deposit.confirmed") markOrderPaid(event.order_id, event.tx_id);
  res.sendStatus(200); // acknowledge fast, do heavy work async
});

Settlement

Set the Solana wallet your USDT should land in under Dashboard → Settlement. Changing it needs your password and sends you an email alert.

• Manual withdraw: move your balance to your wallet any time from the dashboard.
• Auto-forward to TRC20: route Solana USDT to your Tron address through Binance.

SOL gas for settlement is sponsored — you never need to hold SOL.

Plugins

Ready-made plugins let you accept crypto on popular e-commerce platforms without writing code. Each one creates a payment for the order, redirects the customer to checkout and marks the order paid when the webhook arrives.

Errors & limits

Errors are returned as { "error": "message" }.

Go-live checklist

• Create a payment and send a small USDT amount to see it confirm
• Receive and verify a webhook on your server (use “Send test event”)
• Handle partial, overpaid and expired events
• Store the API key and webhook secret in environment variables, not in source control
• Set your settlement wallet