YourAITools

Free x402 endpoint checker

Paste the URL of a paid x402 route. We request it without paying (no payment header is ever sent) and grade the 402 response: does it ask for payment correctly, which x402 versions and networks it supports, and what it costs. Free, no wallet, no signup.

Runs only when you press Check (about 10 checks a minute per network). Results are kept for 60 seconds in this tab, so re-checking the same URL right away shows the saved result.

A point-in-time technical check, not an endorsement. It is an automated, unpaid probe: a good grade doesn’t guarantee that payments settle or that any directory lists you, and it says nothing about data quality, uptime, security or the business behind the URL. It never changes rankings on YourAITools. Fixes from the paid tiers are suggestions to check against the x402 spec. Agents can call the same free check directly: GET https://api.youraitools.co/x402fix/v1/preview?url=…

At a glance

Free check
An unpaid probe: no payment header is ever sent. No wallet, no signup.
Paid option
$19 Verified Settlement Check: a real settlement test and a dated report.
Limits
A point-in-time technical check, not an endorsement.

Read the payment terms from a 402 response

Already have the raw response? Paste the 402 JSON body (x402 v1 or v2) or the base64 PAYMENT-REQUIRED header value to see the x402 version, scheme, network, asset, amount in USDC, payTo, resource and description.

Runs entirely in your browser. Nothing you paste is sent anywhere. Get the raw response with curl -i https://your-endpoint.

Is this your endpoint?

Get it in front of people and agents looking for paid x402 APIs. Listing is free and reviewed for legitimacy and fit. Featured adds a labeled slot at the top of its category for 30 days.

List it freeGet Featured ($29)

Stuck on a fix? Ask in the YourAITools Community (builders getting paid in crypto, x402 help and launches).

Questions

What does the free x402 endpoint checker do?
It sends one unpaid request to the https URL you paste (no payment header is ever sent) and reports whether it answers with a valid x402 402: a grade and score, x402 v1 and v2 support, networks and the price per call. Your browser also tries to read the full payment terms directly: scheme, network, asset, amount in USDC, payTo, resource and description.
Why does it say my browser could not read the 402 directly?
Browsers only let a page read another site’s response when that site allows it with CORS headers. Many x402 servers don’t. The grade still comes from our server-side check; for the full terms, run curl -i on your endpoint and paste the 402 body or the PAYMENT-REQUIRED header into the parser on this page. Allowing CORS and exposing PAYMENT-REQUIRED also helps browser buyers pay you.
Does the checker ever pay or spend money?
No. Both the server-side check and the browser request are unpaid. Nothing is signed and no wallet is needed. The paste parser runs entirely in your browser and sends nothing anywhere.
How is the amount converted to USDC?
x402 amounts are whole numbers in the asset’s smallest unit. When the asset is a known USDC contract or mint (Base, Polygon, Arbitrum One, Ethereum, Optimism, Avalanche, Solana and their common testnets), we divide by 10^6 because USDC has 6 decimals. Any other asset is shown as raw atomic units and not converted.
Is a good grade an endorsement?
No. It is an automated, point-in-time technical check. It does not guarantee that payments settle or that any directory lists you, and it says nothing about data quality, uptime, security or the business behind the URL. It never changes rankings on YourAITools.
My endpoint passes. How do I get it in front of buyers?
List it on YourAITools for free (reviewed for legitimacy and fit, usually live within 3 to 5 days), or get Featured for $29 for 30 days, payable by card or in USDC. Paying never guarantees approval and is refunded if the listing is rejected.

Verified (paid) endpoint check

$19 USDC one-off · Base or Solana

We run a real paid call to your API and send a dated written report. This is a manually fulfilled service, not an instant automated checkout.

What we test

  1. An unpaid request returns HTTP 402 with valid x402 payment requirements: price, network, asset and pay-to.
  2. Those requirements match your listing.
  3. A real test payment from our wallet is accepted and settles on-chain.
  4. The paid request returns a successful response (2xx) with a payment-response header.

What you get

  • A dated report with the request, the 402 response, the settlement transaction and the result.
  • Pass: an “Endpoint checked on YYYY-MM-DD” note on your listing linking to the settlement transaction. Fail: the report, plus one free re-test within 30 days.
  • A point-in-time technical check, not an endorsement. It says nothing about data quality, uptime, security or your business, and it never changes rankings.

How to buy

  1. Email hello@youraitools.co with your HTTPS endpoint URL and request method (GET or POST).
  2. Pay $19 in native USDC on Base or Solana to one of the wallets below, then email the transaction link so we can match your payment. We reply with the report after payment confirms.
Base onlyExplorer
0x3c1A1E01e790Cd326495631B3b38Bd7068F08d6F

USDC on Base only. Other networks or tokens may be lost.

Solana onlyExplorer
FH73WbbUe2UyNzfy72MJs5nT3NxyDf9GrqE7kzjL2Jte

USDC on Solana only. Other networks or tokens may be lost.

Engine self-test

Latest public settle-check report: api.youraitools.co/x402fix/v1/settle-check. Sample settlement on our own endpoint: Basescan tx 0xef0467….

New to x402? Read what is x402. Want your tool listed? Submit it free.

Check your x402 endpoint

Start with the free check. If you need proof that payments settle, order the $19 Settlement Check.

Run the free checkSee the $19 Settlement Check