What we learned getting our own endpoints listed in the Coinbase x402 Bazaar, x402scan, 402index and Poncho.
No sale, no listing. Catalogs index a route only after a payment settles through their facilitator. Each route needs its own first sale, and at least one every 30 days (CDP).
Testnet and tunnels. Testnet resources are never indexed, and tunnel URLs (trycloudflare, ngrok) are rejected as ephemeral.
Description too long or instruction-like. The CDP facilitator rejects descriptions over 500 characters and screens out metadata that reads like instructions to agents.
400 before 402. Return 402 before validating input. A 400 on an empty probe fails health checks and registration.
Sleeping host. Free hosts that sleep fail catalog health probes; a 60-second cold start loses the call and down-ranks you.
Ranking follows usage. New listings start at the bottom of search, even for near-exact phrases. Niche queries with few competitors are where you surface first.
One catalog only. The CDP Bazaar, x402scan, 402index and Poncho index separately. Register with each.
Free quick check
Check any endpoint yourself, no key needed:
curl -X POST https://api.cdp.coinbase.com/platform/v2/x402/validate \
-H 'content-type: application/json' -d '{"resource":"https://your.api/route","method":"POST"}'