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Legible Check – x402 Preflight Inspector
x402
Legible Check – x402 Preflight Inspector is a paid API for AI agents from legible-check.ezealfa.workers.dev, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-29).
Inspects an x402-protected endpoint's 402 response envelope and checks its CDP and PayAI discovery status without making any payment.
Price / call$0.005
Success—
StatusUnknown
How this service works
x402 endpoint preflight: inspect the 402 envelope and check CDP and PayAI discovery status; no payment is made to the target.
Output
Returns the parsed contents of the target endpoint's 402 response envelope (payment metadata, accepted tokens, pricing) along with the endpoint's discovery status on both Coinbase CDP and PayAI, without making any actual payment to the target.
Example use cases
Verify x402 endpoint before integration
“Before I start building my payment flow, can you inspect https://api.myservice.com/data with a GET request and tell me what's in the 402 envelope and whether it's properly listed on PayAI?”
Debug missing PayAI discovery listing
“My x402 endpoint at https://myapp.com/premium-feed isn't showing up in searches — can you do a preflight check with a GET request and see what CDP and PayAI discovery status it reports?”
Audit third-party x402 API payment terms
“I want to use this third-party API at https://partner.io/stream but I don't want to pay yet — can you run a preflight check on it via GET and show me what the 402 envelope says about pricing and payment requirements?”
Technical details
Endpoint
GEThttps://legible-check.ezealfa.workers.dev/x402check?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need to inspect an x402 payment envelope and check discovery status before committing to a payment, or when debugging whether an x402 endpoint is correctly configured and discoverable. Prefer this over directly calling the target when you want a zero-cost, read-only preflight that aggregates 402 envelope data plus CDP and PayAI registration status in one call.
Side effects
- Target URL is not a valid x402 endpoint and returns a non-402 response
- Target endpoint is unreachable or times out
- URL is not HTTPS or is malformed
- HTTP method provided is not in the allowed set (GET, HEAD, DELETE)
- PayAI or CDP discovery lookup fails independently of the target endpoint
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Tags
x402
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