mppx client

mppx is the reference implementation of the Machine Payments Protocol. Any x402-compatible client works with MeshGateway merchants too.

Client in five lines

import { Mppx, evm } from 'mppx/client'
import { privateKeyToAccount } from 'viem/accounts'

const account = privateKeyToAccount(process.env.KEY)
const mppx = Mppx.create({ methods: [evm({ account })] })
const res = await mppx.fetch('https://api.meshgateway.co/m/acme/v1/quote')

The wallet only needs the stablecoin on the merchant's network: USDC on Base, USDG on Robinhood Chain. No ETH required: on Robinhood Chain the one-time Permit2 approval is gas-sponsored by MeshGateway and settlement gas is paid by our relayer.

Validate a merchant

mppx ships a conformance validator you can point at any MPP endpoint:

npx mppx validate https://api.meshgateway.co/m/demo

It checks the 402 challenge shape, the discovery document, and header compatibility.