The Machine Payments Protocol (MPP) is an open standard for autonomous machine-to-machine and agent-to-agent payments. It defines how one agent discovers a price, authorizes a payment, and settles it programmatically — no human in the loop — so services can charge AI agents directly. MPP sits alongside x402, A2A and AP2 in the emerging agentic-payments stack.
The projects below implement, extend or build on MPP: reference servers and clients, agent frameworks with MPP support, and tooling for price discovery and settlement between machines.
Choosing between rails? See x402 vs MPP for a layer-by-layer comparison, or browse all agent payment protocols.
The MPP category right now
The directory currently tracks 142 MPP projects. mppx leads the group with 154 stars, and 2 of them have cleared 100 stars. Half the group sits at 0 stars or below, which is the honest shape of this space today: a short head of real adoption and a long tail of experiments.
TypeScript (41%) and Python (13%) dominate the implementation languages here, and tempoxyz is the most prolific publisher with 5 MPP repositories. The recurring GitHub topics are mpp, ai-agents, machine-payments.
40 of the 142 projects were updated in the last 30 days and 62 in the last 90 (44%), so activity is uneven — check the last-commit date before adopting. 26 have had no commit for over a year. The newest entrant is mpp-swift, first published 2026-05.
Figures recomputed from the tracked repositories on every build.
Compare: x402 vs MPP · All agent payment protocols
