x402 · BNB Chain · chain 4663

Charge for an API call
without an account on either side.

Wrap a route, name a price. The caller pays per request in USDT and the money lands in your wallet — no signup, no subscription, no processor in between.

ca:0xdc263f0f90ce280ba9c791a7f4f5127c9e7f7777 How it works
app/api/your-endpoint/route.ts
import { withX402Payment } from '@/lib/x402/middleware';

export const POST = withX402Payment(handler, "0.01");
Protocol fee
0%
Settles in
USDT
Accounts required
none

How a paid request works

Four steps, all of them in lib/x402/middleware.ts. No facilitator required, no account anywhere in the loop.

  1. 01

    The request arrives without payment

    Your handler is wrapped once. FeeLess intercepts before your code runs.

    GET /api/data/weather?city=Istanbul
  2. 02

    FeeLess answers 402

    The response carries the price, your address, the chain ID and the tokens you accept.

    HTTP/1.1 402 Payment Required

{
  "amount": "0.01",
  "currency": "USDT",
  "recipient": "0x…",
  "network": "4663"
}
  3. 03

    The caller pays on chain

    A real USDT transfer on BNB Chain. The caller retries with its transaction hash — not a promise to pay, but a receipt.

    X-Payment: {"from":"0x…","amount":"0.01",
  "token":"USDT","chainId":"4663",
  "transactionHash":"0x13c8…"}
  4. 04

    FeeLess reads the receipt

    It confirms the transfer landed, paid the right address, cleared the price, and has not been spent before. Only then does your handler run.

    HTTP/1.1 200 OK
x-payment-chain: BSC

{ "city": "Istanbul", "temperature": 22 }

The transaction hash is also the replay key: one transfer buys exactly one response. Reuse it and the request is rejected. What is still open is a shared store for that ledger, so replay protection holds across serverless instances — see the chain docs.

One wrapper on the handler you already wrote

Your route keeps its signature. The price is the second argument.

app/api/your-endpoint/route.ts
import { withX402Payment } from '@/lib/x402/middleware';

async function handler(req: NextRequest) {
  // Your API logic here
  const data = await processRequest(req);
  return NextResponse.json({ data });
}

// Add payment requirement - that's it!
export const POST = withX402Payment(handler, "0.01");
caller side
// 1. Pay on BNB Chain
const hash = await USDT.transfer(recipient, amount);

// 2. Call again with the receipt
const response = await fetch('/api/your-endpoint', {
  method: 'POST',
  headers: {
    'X-Payment': JSON.stringify({
      transactionHash: hash,   // proof, not a promise
      amount, token: 'USDT', chainId: '4663'
    })
  },
  body: JSON.stringify({ data })
});

Selling data about the assets the chain carries

Reading a tokenised equity on BNB Chain is permissionless. Moving one is not. So these endpoints sell data about them and settle in USDT — no securities held, no upstream key, and every answer checkable against the explorer.

/api/rwa/tokens $0.02 USDT Every BSC stock token, supply read live
/api/rwa/token $0.01 USDT One tokenised equity, by ticker
/api/rwa/holdings $0.02 USDT An address’s tokenised equity position
/api/chain/receipt $0.02 USDT Did this transaction actually pay me?
/api/chain/balance $0.01 USDT BNB and token balances for any address
/api/chain/token $0.01 USDT BEP-20 metadata, read live from chain 4663
/api/data/crypto $0.015 USDT Spot prices, no API key on your side
/api/tools/qrcode $0.005 USDT Half a cent a QR code
Call them in the playground →