APIs that AI agents can find, use, and pay

mpp.land is the open registry for the Machine Payments Protocol, a standard that lets software pay for API calls at the HTTP layer. No API keys, no accounts, no vendor lock-in.

105 services indexed
105 reachable now
430ms median response

How it works

1
Discover

Service publishes an OpenAPI spec with x-payment-info on each paid endpoint.

2
Challenge

Client calls the endpoint, gets a 402 Payment Required response with payment details.

3
Pay

Client submits payment proof in the next request. Service verifies and responds with data.