Machine-readable contract
Response schemas
Every JSON response on this site is self-describing. Each one carries a three-field envelope whose $schema pointer resolves to the JSON Schema document for that shape, so an agent can validate a response before it influences a decision.
The envelope
Three top-level fields appear on every JSON response:
Compatibility rules
same version Additive fields
A new optional field is backward compatible and does not change the version.
major bump Remove / rename / resemantize
Removing or renaming a field, or changing what it means, is a new major version.
documented New enum value
A new recommendation or grade value is a documented version change, because strict buyers may reject unknown values.
Two closed enums are worth pinning: recommendation is one of proceed, caution, avoid, parameterize, unverified, not-payable. grade is one of A, B, C, D, F, or ? for unmeasured.
Data & scoring
11 schemas-
x402-trustFull trust report for one endpoint: score, grade, recommendation, component breakdown, advertised price, and 30-day on-chain settlement stats. -
x402-trust-bulkBatch trust scores for up to 500 endpoints in a single paid call. -
x402-trust-previewFree sample reports for three fixed endpoints, showing the full paid shape across the quality range. -
x402-historyRaw observation time-series for one endpoint: list/delist events, price and payTo changes, and per-probe results. -
similarThe endpoints whose advertised purpose matches a URL and currently out-score it. -
semantic-searchFree-text semantic search over the catalog: the closest endpoints by meaning, with similarity, score, grade, and description. Discovery only, no verdicts. -
statsAggregate ecosystem snapshot: listings, reachability, and 30-day settlement volume. -
leaderboardThe top trust-scored endpoints, free. -
reportThe full State of x402 report, the JSON behind /trust/report. -
facilitatorsPer-facilitator settlement volume leaderboard. -
facilitatorDetail for one facilitator, with per-chain volume and 90-day history.