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PreFlight Checker – x402 Service Auditor
x402
PreFlight Checker – x402 Service Auditor is a paid API for AI agents from x402-api-catalog.onrender.com, paid per call via x402, $1/call, status unknown (last checked 2026-09-15).
Audits an x402-enabled API endpoint for the specific failure modes that cause aggregators to mark it as down or its 402 challenge as unreadable, returning concrete diagnoses and fixes.
Price / call$1
Success—
StatusUnknown
How this service works
Audits another x402 service for the exact failure modes that cause aggregators (agent-tools.cloud, x402scan, Bazaar) to mark it 'down' or make its 402 challenge unreadable: missing/invalid /.well-known/x402 descriptor, an unpaid request returning 500/404 instead of a clean 402, a malformed or missing payment-required challenge, and drift between the descriptor's advertised terms and the live challenge. Returns a concrete diagnosis and fix for each failing check, not just pass/fail.
Output
Returns an audit report with a numeric score, an overall verdict, and per-check diagnoses covering: /.well-known/x402 descriptor presence and validity, whether unpaid requests return a clean 402 (not 500/404), whether the payment-required challenge is well-formed, and whether the descriptor's advertised terms match the live challenge — each with a concrete fix recommendation.
Example use cases
Debug x402 service marked down
“My x402 API at https://my-payments-api.com keeps getting flagged as down on agent-tools.cloud — can you audit it and tell me exactly what's broken and how to fix it?”
Validate 402 challenge before launch
“Before I list my new paid endpoint at https://api.mybiz.com/premium on Bazaar, can you check that it returns a proper 402 challenge and that my /.well-known/x402 descriptor is valid and consistent with it?”
Fix descriptor and live challenge drift
“My x402 service at https://data-api.io is live but aggregators say the payment terms don't match — can you probe the specific path /api/data and diagnose whether the descriptor is drifting from the actual 402 response?”
Technical details
Endpoint
GEThttps://x402-api-catalog.onrender.com/api/x402-doctorWhen to prefer
Choose this endpoint when you need to understand specifically why an x402-enabled API is being flagged as down or broken by aggregators like agent-tools.cloud, x402scan, or Bazaar. It is purpose-built for the x402 payment protocol and goes beyond simple uptime checks by diagnosing descriptor validity, challenge format, and drift between advertised and live payment terms — making it the right tool for developers debugging x402 integration issues rather than general API health monitoring.
Side effects
- Target URL is unreachable or times out — returns error indicating the service could not be probed
- Target service returns an unexpected response format that prevents analysis
- Missing required 'url' query parameter — returns 400 validation error
- Audited service has no x402 infrastructure at all — returns low score with full diagnostic breakdown
- Rate limit or payment failure for the $1 USDC per call fee
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"url": "https://example-service.onrender.com",
"fixes": [],
"score": 40,
"checks": [],
"verdict": "broken: aggregators will show this as down"
}
}Tags
x402
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