@cheapay/x402-express

HTTP-native Solana payment protocol for APIs. Accept USDC/SOL micropayments with one-line middleware integration.

Features

• Solana-first: Designed for Solana payments (USDC/SOL) out of the box
• Express.js middleware for easy integration
• Simple, secure, and scalable micropayment support
• TypeScript support

Installation

npm install @cheapay/x402-express
# or
yarn add @cheapay/x402-express
# or
pnpm add @cheapay/x402-express

Quick Start (Solana)

Accepting SOL (native token)

import express from 'express';
import { paymentMiddleware } from '@cheapay/x402-express';
import { Network } from '@cheapay/x402';

const app = express();

app.use(
  '/api/paid',
  paymentMiddleware({
    chain: 'solana',
    recipient: 'YourSolanaAddressHere', // Replace with your Solana address
    amount: '0.01', // Amount in SOL
    network: Network.MAINNET, // or Network.DEVNET, Network.TESTNET
    // currency: 'SOL', // (optional, native SOL is default)
  })
);

app.get('/api/paid', (req, res) => {
  res.json({ message: 'Payment received! Access granted.' });
});

app.listen(3000, () => {
  console.log('Server running on http://localhost:3000');
});

Accepting USDC (SPL token)

import express from 'express';
import { paymentMiddleware } from '@cheapay/x402-express';
import { Network, TokenMint } from '@cheapay/x402';

const app = express();

app.use(
  '/api/paid-usdc',
  paymentMiddleware({
    chain: 'solana',
    recipient: 'YourSolanaAddressHere', // Replace with your Solana address
    amount: '0.50', // Amount in USDC
    network: Network.MAINNET, // or Network.DEVNET, Network.TESTNET
    mint: TokenMint.USDC.mainnet, // Use TokenMint.USDC.devnet for devnet
  })
);

app.get('/api/paid-usdc', (req, res) => {
  res.json({ message: 'USDC payment received! Access granted.' });
});

app.listen(3001, () => {
  console.log('Server running on http://localhost:3001');
});

API

paymentMiddleware(options)

• chain: Blockchain to use ('solana' recommended)
• recipient: Solana address to receive payments
• amount: Payment amount (string or number)
• network: Solana network (use Network.MAINNET, Network.DEVNET, or Network.TESTNET)
• mint: (optional) SPL token mint address (e.g., TokenMint.USDC.mainnet)
• ...other advanced options (see TypeScript types)

License

Apache-2.0