Payments that settle inside the request.

import { paymentMiddleware } from "@blockpay402/express";

// Unpaid requests get a 402 quote. Paid ones reach your handler.
app.use(
  paymentMiddleware({
    facilitator: { url: FACILITATOR_URL, apiKey: API_KEY },
    network: "sui:mainnet",
    payTo: "0x9c4e…a71f",
    routes: {
      "GET /api/data": {
        price: "$0.01",
        description: "Real-time market data",
      },
    },
  })
);

app.get("/api/data", (req, res) => {
  // Runs after the payment is verified.
  res.json(getMarketData());
});

GET /api/data HTTP/1.1

HTTP/1.1 402 Payment Required
PAYMENT-REQUIRED: eyJ4NDAyVmVyc2lvbiI6Miwi…
{
  "x402Version": 2,
  "accepts": [{
    "scheme": "exact",
    "network": "sui:mainnet",
    "amount": "10000",
    "asset": "0xdba3…::usdc::USDC",
    "payTo": "0x9c4e…a71f",
    "extra": { "gasless": true }
  }]
}

GET /api/data HTTP/1.1
PAYMENT-SIGNATURE: eyJ4NDAyVmVyc2lvbiI6Miwi…

HTTP/1.1 200 OK
PAYMENT-RESPONSE: eyJzdWNjZXNzIjp0cnVlLCJ0cmFuc2FjdGlvbiI6…