universal-pay

Pay any HTTP 402 merchant on any chain. Auto-detects x402 or MPP, bridges funds via Across.

Install

npm install universal-pay

Usage

import { createUniversalFetchWithAcross } from 'universal-pay'

const client = createUniversalFetchWithAcross({
  privateKey: process.env.UNIVERSAL_PAY_KEY as `0x${string}`,
})

// Pays automatically — detects protocol, bridges if needed
const response = await client.fetch('https://merchant.example.com')

How It Works

1. Probe — makes the request, gets 402 Payment Required
2. Detect — reads headers: PAYMENT-REQUIRED = x402, WWW-Authenticate = MPP
3. Bridge — if funds are on the wrong chain, bridges via Across
4. Pay — replays the request through the native protocol adapter

Config

createUniversalFetchWithAcross({
  privateKey: process.env.UNIVERSAL_PAY_KEY as `0x${string}`,  // required
  polyfill: false,                  // replace globalThis.fetch (default: false)
  across: {
    originChainIds: [42161, 8453],  // chains to scan for funds
    rpcs: { 42161: 'https://...' }, // custom RPCs
  },
})

License

MIT

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