Machine Payments Protocol (MPP)
Open standard for machine-to-machine payments over HTTP 402, co-developed by Tempo and Stripe; charge per API request, tool call or content.
Tags
Description
Challenge/Credential/Receipt flow with HTTP, MCP/JSON-RPC and WebSocket transports; charge, session (metered) and subscription intents; payment methods include Tempo stablecoins, Stripe cards, Lightning, EVM (with x402 exact compatibility) and more. Official SDKs in TypeScript (mppx), Python, Rust, Go and Ruby.
Agent access
Related
- x402: Open standard for internet-native payments built on HTTP 402, letting APIs and agents pay per request across crypto and fiat networks.
- Stripe for Agents (Stripe AI): Stripe's agent toolkit: plugins, remote MCP, agent skills and SDKs for usage-based billing, agentic commerce and machine payments.
- L402 (Lightning HTTP 402): Lightning Labs standard for paying for and authenticating to APIs with Bitcoin Lightning payments; Aperture is the reference reverse proxy.
Guides & comparisons
- Pay for an API as an agent with x402 (Guide): How an agent pays per request for an HTTP API or MCP tool with x402 v2, from reading the 402 response to signing a USDC payment with spend caps, on testnet first.
- Agent payment protocols compared (Comparison): x402, MPP, L402, ACP, AP2 and UCP compared on what each standardizes, payment rails, wire format, governance, spec status and SDKs, so you can tell machine-payment protocols from agent-checkout protocols.
- Agent that can buy things (Stack): The pieces for an agent that pays for APIs per call with x402 stablecoins and buys from merchants with controlled virtual cards, with spend limits, proof of user intent and a full audit trail.
Sources
Machine-readable
- JSON
- Markdown
- Source file on GitHub (edit via pull request)