How an agent finds PayAPI: pay per call API, no API key
Four commands, all real, all runnable right now. Discovery is free and settles nothing. You only spend when you call a provider directly and answer its own payment challenge.
1. Search the catalogue
Free text over every live listing. Returns settlement-verified listings by default; add verified_only=false to include listed-but-unpaid ones.
curl -sS "https://payapi.market/agent/search?q=property"2. Read one listing in full
By slug or id. Gives you base_url, price range, network, the verification state, and a reliability object: score (0 to 100 or null), band, and computed_at. The same object is on every search and list result, and on the MCP tools.
curl -sS "https://payapi.market/agent/get?id=uk-hmo-licence-api"3. Or take the whole machine-readable contract
An OpenAPI 3.1 document generated at request time from the live catalogue. The discovery endpoints are real paths; every listing is a tag carrying its price, network, verification state and a link to its own base_url.
curl -sS https://payapi.market/openapi.json4. Call the API and pay its challenge
PayAPI Market is not in the payment path. Request the provider base_url unpaid, read the HTTP 402 challenge it returns, and settle it from your own wallet. The provider is paid directly and keeps 100%.
curl -sS -i "https://hmo.payapi.market/v1/licences?postcode=M1+1AE"Or connect over MCP
A stateless server exposing the same three operations as tools: search_apis, list_apis and get_api. Every method is free, including initialize and tools/call. It never returns a 402 and never spends anything: it hands back base_urls and you pay the provider yourself.
{ "mcpServers": { "payapi": { "url": "https://payapi.market/mcp" } } }Manifest at /.well-known/mcp.json. This is a different server from the first-party property-tools endpoint advertised as mcp in /.well-known/x402, whose tools/call is paid.
Reliability is not a star rating
Nobody rates these APIs, and there are no reviews to game. The reliability score is computed from things that either happened or did not: whether we paid for a route and got product back, how the endpoint has answered health checks since, and whether the wallet in its payment challenge still matches the one on record. Recent evidence counts for more than old evidence, so a score decays if nothing new happens.
Read band rather than the bare number: strong is 80 and above, established is 50 to 79, thin is 26 to 49, caution is 25 and under, and unscored means we have not computed one for that listing yet. Unscored is not a criticism; it usually means the listing is new.
What it is not: a security audit, a promise the API will be up when you call it, or a claim about output quality beyond the one route we paid for. Treat it as one input to your own decision, not a verdict, and check computed_at to see how fresh it is.
What verified means here
A listing is settlement-verified only when PayAPI Market paid for a real call to it from its own wallet and got real product back, with the payment recorded on-chain. It is evidence per listing, not a guarantee per route: a listing with several routes may have had only one paid for. Listings we have not paid for are shown as listed, never described as verified.