MPP — Machine Payment Protocol

What is MPP?

MPP (Machine Payment Protocol) is a micropayment system built for AI agents. It uses pathUSD on the Tempo blockchain for near-instant, low-fee payments. Agents pay per API call using the mppx SDK.

How it works

Agent sends a request to a paid endpoint

Server returns HTTP 402 with a WWW-Authenticate: Payment header

The header contains: realm, amount, recipient, and network details

Agent pays using the mppx SDK

Agent retries with payment proof

Server verifies and responds

Key concepts

pathUSD: A stablecoin on the Tempo chain (1 pathUSD = 1 USD)
mppx: The CLI and SDK for making and receiving MPP payments
Sub-second finality: Payments confirm almost instantly
Low fees: Designed for micropayments (fractions of a cent)

How to add MPP to your service

1. Install mppx

npm install mppx

2. Create a wallet

npx mppx account create
npx mppx account fund  # for testnet

3. Add Express middleware

import { mppMiddleware } from 'mppx';

app.use('/api/paid-endpoint', mppMiddleware({
  amount: 0.01, // in USD
}));

4. Set environment variables

MPP_SECRET_KEY=your_secret_key
MPP_RECIPIENT_ADDRESS=your_wallet_address

Spec maturity

Production-ready. Live on the Tempo network with active services including AgentNews.

Learn more

mppx on npm — SDK, CLI, and Express middleware

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