Tools for the x402 payment protocol
Free tools for the x402 payment protocol: see what an endpoint charges, verify a payment challenge before you sign it, test a spend policy, and debug a failed payment. Challenge decoding and policy evaluation here run the same code the tx402 SDK runs before it pays — so what these tools say is what the SDK would do.
402 Inspector
S4 · not live yetWhat does this x402 endpoint charge?
See what an x402 API charges before you call it: price per request, token, network and payout address, decoded by the same strict decoder the tx402 SDK uses before it pays.
402 Verify
S5 · not live yetVerify an x402 payment challenge
Check an x402 payment challenge for problems before signing: strict decoding, canonical atomic amount, recognized network and asset, and whether the resource origin matches.
402 Policy Playground
S3 · not live yetTest an x402 spend policy against a real challenge
Try an x402 spend policy against a real payment challenge and see which rule allows or blocks it, in evaluation order, with the exact error your code would raise.
402 History
S7 · not live yetHow has this x402 endpoint's price changed?
See how an x402 endpoint's price, payout address, availability and latency have changed over time, with every terms change dated and recorded.
402 Compare
S8 · not live yetCompare x402 APIs side by side
Compare x402 endpoints side by side on price per call, network, asset, observed availability and latency — with explicit gaps where there is not enough data yet.
402 Replay
S10 · not live yetWhy did my x402 payment fail?
Debug a failed x402 payment: reconstruct the lifecycle from your trace or typed error, find the phase that broke, and learn whether retrying is safe or would pay twice.
402 Watch
S9b · not live yetGet alerted when an x402 endpoint's terms change
Get alerted when an x402 endpoint changes its price or its payout address, with the recorded change that triggered the alert attached to every notification.
Built for agents too
Every page serves three representations of the same result, so an agent never has to scrape HTML.
| JSON | curl -H 'Accept: application/json' tools.tx402.io/inspect?url=… |
|---|---|
| Markdown | curl -H 'Accept: text/markdown' tools.tx402.io/inspect?url=… |
| Or just | curl tools.tx402.io/inspect.md?url=… |
| Schemas | /api/v1/schemas |