Paste a URL. We fetch it, parse the 402 PAYMENT-REQUIRED header, and show you what your buyers actually see. No USDC sent. Own the endpoint? Claim it right after.
Watch402 watches the two x402 discovery catalogs — the PayAI Network Bazaar and Coinbase CDP x402 Discovery — covering 40,937 paid-API endpoints. Each listing is rechecked on a schedule matched to its health: anything serving payments is verified every day, dead endpoints are swept weekly. We hit your endpoint, parse the live HTTP 402 PAYMENT-REQUIRED challenge, and compare price, payout wallet and network against what the catalog advertises. When they stop matching, it shows up here.
The largest x402 discovery catalog, at facilitator.payai.network/discovery/resources. Watch402 ingests every listing — resource URL, advertised price in USDC atomic units, payout wallet, network and scheme — and re-probes each endpoint daily with the HTTP method and example inputs the listing declares.
Coinbase's official catalog via the Developer Platform, at api.cdp.coinbase.com/platform/v2/x402/discovery/resources. ~15,000 additional listings, many not present in any other index. Same daily treatment: live 402 fetch, header parse, full diff against the advertised terms.
We request the exact resource URL with its declared method (GET/POST), example path and query parameters, and example body. We parse the base64 PAYMENT-REQUIRED header from the 402 response, extract every accepts[] entry, and diff price, payTo wallet, network and scheme against the catalog. Verdicts: live · drifted · broken · misconfigured · unreachable.
Every other x402 trust tool warns the buyer before they pay. We watch from your side of the table: what your PayAI or Coinbase listing looks like right now, and whether it matches what the catalog promises.
Price drift. ScoutScore's February 2026 audit found 58% of Bazaar listings advertise the wrong price. Every endpoint here is rechecked daily and diffed against its advertised terms.
No signup, no API key, no card. Paste any Bazaar URL above and see exactly what buyers see. Daily monitoring is free while we're in beta; alerts and history become paid tiers later.
If you sell on x402, you have a listing in a discovery catalog — the PayAI Network Bazaar, Coinbase CDP x402 Discovery, or both. That listing can break in dozens of ways: your wallet changes, your price drifts, your server dies, your resource URL 404s. The protocol won't tell you. Your buyers won't tell you. They'll just stop paying.
Watch402 is the thing that tells you. We recheck every listing daily, parse the live 402 challenge, and diff it against what the Bazaar advertises — price, wallet, network, scheme. Everything we find is public on this page, free.
The demo above works on your endpoint right now. No signup. Per-seller history and webhook alerts are rolling out next; the monitoring itself is live today.