Machine Payment Control Protocol (MPCP)

Protocol Version: MPCP 1.0

A protocol for verifiable machine-to-service payments.

Autonomous vehicles, AI agents, and machines increasingly pay for real-world services like parking, charging, and tolls.

How MPCP works

A machine payment is accepted only if the recipient can verify a chain of signed artifacts:

Fleet Policy → PolicyGrant → SignedBudgetAuthorization → SignedPaymentAuthorization → SettlementIntent → Settlement

Each step narrows what the machine is allowed to do.

→ See the full reference flow

MPCP is not a settlement rail — it is the authorization layer above settlement.

Specification Contents

• Overview — What is MPCP, Problem Statement, Design Goals
• Architecture — System Model (includes architecture diagram), Authorization Chain, Actors, Reference Flow
• Protocol — MPCP Spec, Artifacts, and artifact definitions (PolicyGrant, SBA, SPA, SettlementIntent, etc.)
• Guides — Integration Guide (start here), Build a Machine Wallet, Fleet Payments, Dispute Resolution
• Diagrams — Visual reference
• Roadmap — Implementation roadmap

Reference Implementation

The reference implementation and mpcp-reference repository.