IBANforge

x402 Micropayments

IBANforge uses the x402 protocol for authentication and billing. Instead of API keys and monthly subscriptions, you pay a tiny amount of USDC per request — automatically.

How it works

Think of it like a toll road: each API call costs a fraction of a cent, and the payment happens inline with your HTTP request.

  1. Your client sends an API request with a X-PAYMENT header containing a signed USDC payment
  2. IBANforge verifies the payment through the x402 facilitator
  3. If valid, the request is processed and the response is returned
  4. If missing or invalid, you receive a 402 Payment Required response with pricing details

No signup. No API keys. No rate limits. You only pay for what you use.

Pricing

| Endpoint | Cost per request | |---|---| | POST /v1/iban/validate | $0.005 USDC | | POST /v1/iban/batch | $0.020 USDC | | GET /v1/bic/:code | $0.003 USDC |

The 402 response

When you call a paid endpoint without a valid payment header, you receive:

HTTP/1.1 402 Payment Required

{
  "error": "Payment Required",
  "accepts": {
    "scheme": "exact",
    "network": "base",
    "maxAmountRequired": "5000",
    "resource": "https://api.ibanforge.com/v1/iban/validate",
    "description": "IBAN validation — $0.005 USDC",
    "mimeType": "application/json",
    "payTo": "0x...",
    "maxTimeoutSeconds": 300,
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"
  }
}

This response tells your client exactly what to pay, where, and on which network (Base L2).

Supported clients

Any HTTP client that implements the x402 protocol can pay automatically. The protocol is an open standard — here are some options:

x402 SDK (recommended)

The official x402 TypeScript SDK handles payment automatically:

import { paymentMiddleware } from "x402/client";

const client = paymentMiddleware(fetch, {
  walletPrivateKey: process.env.WALLET_PRIVATE_KEY,
});

// Payments happen automatically — just use fetch as usual
const response = await client(
  "https://api.ibanforge.com/v1/iban/validate",
  {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({ iban: "CH9300762011623852957" }),
  }
);

Manual integration

If you prefer to handle payments yourself, the flow is:

  1. Make a request to the API endpoint
  2. If you get a 402, parse the accepts object from the response
  3. Create and sign a USDC transfer on Base for the specified amount
  4. Retry your request with the X-PAYMENT header containing the signed payment

Free testing

You do not need any USDC to try the API. Use the demo endpoint:

curl https://api.ibanforge.com/v1/demo

This returns example validations for free, so you can explore the response format before setting up payments.

Network

All payments happen on Base (Coinbase L2), which means:

  • Transaction fees are under $0.01
  • Settlement is near-instant (2 seconds)
  • USDC is the native stablecoin — no price volatility

FAQ

Do I need to create an account? No. The payment itself is your authentication.

What if I run out of USDC? The API returns 402 Payment Required. Your existing data and results are not affected.

Is there a minimum balance? No minimum. You need enough USDC on Base to cover one request (as low as $0.003).

Can I use this from a backend without exposing my wallet? Yes. Keep your private key in environment variables on your server. The x402 SDK handles signing without broadcasting transactions on-chain for every request.

Learn more