- CollectionCommerce & Payments
- Classificationagent-native
- LicenseMIT (wevm/mppx); protocol/site repos are separate (see Official Repo)
- MCPAvailable
- Agent SkillUnavailable
- InterfacesMCP · CLI · SDK · http · API
- Verified2026-10-13
What it does
MPP (Machine Payments Protocol) is an open pay-in-the-request standard. Official llms.txt: it standardizes HTTP 402 for machine-to-machine payments. Flow: Challenge → Credential → Receipt. A server answers 402 Payment Required with accepted methods and price; the client pays (Tempo stablecoins, cards/Stripe, Lightning, EVM, and other documented rails) and retries; the server returns a Payment-Receipt.
It is designed so agents do not need pre-provisioned API keys or a checkout form (agentic payments). Sessions support metered pay-as-you-go (including per-token). mppx is the TypeScript interface: client polyfill, server charge, CLI, and a payments Proxy.
Distinct from catalog x402 / OpenLibx402: those are the IETF-adjacent HTTP 402 / PAYMENT-REQUIRED crypto rail. MPP adds cards, bank-style Stripe paths, Lightning, Tempo sessions, and can also speak x402 exact from one SDK. Distinct from AP2 / UCP: those are checkout mandates and a commerce language, not inline HTTP 402. Distinct from Skyfire / AgentsPay / Circle Agent Stack / Payman AI: hosted KYA/wallets, not an open pay-in-the-request protocol.
Agent-facing interfaces
- Interaction pattern: SDK + HTTP 402
- Catalog protocols: MCP, CLI, SDK, http, API
- MCP: ✅ First-class transport and SDK, not a single hosted “MPP MCP server.”
- Agent Skill: ⚠️ No official npx skills add package. Docs ship copy-paste prompt mode for agents.
- Onboarding type:
sdk
How agents onboard
Interaction pattern: SDK + HTTP 402
npm i mppx
See the full onboarding section in the dossier.
Protocol surface
| Interface | Detail |
|---|---|
| Spec / site | https://mpp.dev — site source tempoxyz/mpp |
| Protocol drafts | tempoxyz/mpp-specs — Payment HTTP auth scheme |
| TypeScript SDK | npm i mppx — wevm/mppx |
| CLI | npx mppx account create then mppx example.com |
| MCP | Client wrap + server Transport.mcpSdk() |
| Docs MCP | https://mpp.dev/api/mcp |
| x402 interop | Same mppx fetch can satisfy x402 exact |
Verification
Last verified 2026-10-13.
Sources:
- https://api.github.com/repos/wevm/mppx