Protocols
MPP
MPP, the Machine Payments Protocol, is an open protocol co-authored by Stripe and Tempo so an agent can pay for an API without a checkout page. A server can answer with HTTP 402 and payment details. One method is a Tempo session: a payment channel where the client deposits onchain and signs vouchers for metered use.
Explanation
Stripe's session docs describe four parties for the hosted variant: the agent, the server, Tempo, and Stripe. The agent deposits into escrow. The server charges for work in small increments and, in the Stripe integration, records settlements to a Stripe balance in whole cents, with a sub-cent remainder forfeited when a session closes. The open session method on mpp.dev uses the TIP-1034 escrow precompile. The client opens a channel, signs cumulative vouchers, and the server verifies those signatures locally, then settles in batches.
This index counts only the onchain piece it can attribute without a private API. That is a Settled event on Tempo mainnet, chain id 4217, and only the event's deltaPaid when it is greater than zero. ChannelClosed is not indexed, because it repeats lifetime settled value. Stripe card charges, shared payment tokens, and per-merchant Tempo deposit addresses are real MPP products and are not this feed. Counting them as well as the precompile would either miss private data or double-count.
Current index
| Period | Volume | Payments | Payers | Sellers |
|---|---|---|---|---|
| 24 hours | $9,653 | 110,112 | 23,380 | 7,478 |
| 7 days | $40,132 | 186,961 | 3,727 | 2,456 |
| 30 days | $45,963 | 215,671 | 3,792 | 2,482 |
Backfill in progress on base, solana, tempo. A checkpoint is still open, so recent totals can still move.
Live data
Related terms
Sources
- Machine Payments Protocol — Stripe
- Accept streaming payments with MPP sessions — Stripe
- Sessions: low-cost high-throughput payments — MPP
- Agent GDP methodology — Agent GDP