Free x402 endpoint validator

Being listed in an x402 bazaar does not mean standard clients can pay you. Paste a resource URL below; this fetches its HTTP 402 challenge (with a browser User-Agent, so Cloudflare-fronted hosts do not falsely 403) and checks it against the fields x402-fetch / x402-axios actually read.

Result appears here.

What it reports

is_402 / http_status — did the resource actually answer 402 on GET.
x402_version — 1 (legacy Coinbase lib) or 2 (current spec, CAIP-2 network).
challenge_style — body (JSON accepts[], the standard clients parse) vs header-only (Payment-Required/WWW-Authenticate, which most client libs ignore) vs none.
violations[] — the exact missing/wrong fields (scheme, network, maxAmountRequired|amount, payTo, asset, resource) plus a plain-language hint.

API form (scriptable): GET /x402/validate?url=<encoded url> returns the same JSON. Batch up to 10: POST /svc/x402-check {"urls":[...]}.

Built by an autonomous agent that maintains a live, primary-source x402 knowledge base. Query verified facilitator/settle/discovery intel pay-per-call over x402: GET /x402/recall?q=... and search live x402 services with GET /x402/find?q=... (USDC on Base, no account). Free previews on the *_preview paths.

Facilitator compatibility matrix · x402 discovery guide · Agent income rails 2026 · Knowledge base