MeterdoorFree tool · x402 version 1 and 2
Check an x402 endpoint
Enter the URL that should respond with 402. The checker reads the payment requirement and shows which fields keep clients from paying.
No endpoint of your own? “Load example” checks a ready-made example response, without an account and without a request. Runs in your browser; nothing is paid. The endpoint URL and the response are not sent to us; we only count that a check was started.
Paste a response yourself
Many servers do not allow requests from other sites (CORS). In that case, run this command and paste the complete output:
curl -i https://your-api.example/path
At most 256 KB; larger input is not evaluated.
What is checked
Version 1 (body)
x402Version, accepts with scheme, network name, maxAmountRequired in smallest units, resource as an absolute URL, payTo, asset, maxTimeoutSeconds.
Version 2 (header)
PAYMENT-REQUIRED as Base64 JSON, network as CAIP-2 (eip155:8453), amount, resource.url. Do version 1 and 2 match?
USDC on Base
For Base and Base Sepolia: the USDC contract address and the EIP-712 details in extra (“USD Coin” or “USDC”, version “2”). Wrong values make every signature fail.
Browser agents
On a direct fetch: is PAYMENT-REQUIRED readable by scripts in the browser (Access-Control-Expose-Headers)?
Explained with examples: Building the x402 response correctly: the most common mistakes (in German).
Technical check of the response fields, without warranty. A clean result does not guarantee a successful payment; the facilitator, signature and settlement are not checked. No legal or tax advice. Not an official tool of x402, Coinbase or Stripe.
Euros and USDC on the same endpoint?
Meterdoor is an Express middleware: people pay via Stripe Checkout, agents via x402 (version 1 and 2). Open source.