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x402 Doctor – Delivery Check
x402
x402 Doctor – Delivery Check is a paid API for AI agents from x402-doctor.fizzl.eu, paid per call via x402, $0.25/call, status unknown (last checked 2026-10-17).
Autonomously purchases an x402 endpoint once with its declared example input (up to $0.1 USDC on Base), validates the response against the endpoint's declared output schema, and measures the on-chain charge, returning a job ID immediately with results available within ~30 minutes.
Price / call$0.25
Success—
StatusUnknown
How this service works
Does this x402 endpoint really deliver? x402 Doctor buys it once with the example input its own listing declares (at most $0.1, USDC on Base), checks the answer against the declared output schema and measures the charge on chain. Answers with a job id at once; the result is public, usually within 30 minutes. For sellers who want proof, and buyers before a big order.
Output
Returns a job ID immediately upon submission. Within approximately 30 minutes, the public result includes whether the endpoint delivered a valid response matching its declared output schema, the actual on-chain USDC charge recorded on Base, and whether the endpoint behaves as advertised. The result is publicly accessible via the job ID.
Example use cases
Buyer due diligence before bulk order
“I'm about to repeatedly call this x402 endpoint at https://weather-x402.example.com/forecast and it costs $0.05 per call — can you run a delivery check on it via GET to confirm it actually returns valid data and charges the right amount before I commit?”
Seller proving endpoint legitimacy
“I listed my x402 API at https://myapi.example.com/summarize on the marketplace and I need proof it works as advertised — can you do a delivery check on it with a GET request so I can show buyers it's legit?”
Marketplace listing verification
“I found this x402 endpoint at https://data-provider.example.com/prices that claims to return real-time prices, but I'm not sure it's trustworthy — can you buy it once via GET and check whether the response actually matches its declared schema?”
Technical details
Endpoint
GEThttps://x402-doctor.fizzl.eu/api/v1/delivery-check?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need trustworthy, on-chain-verified proof that a specific x402 endpoint actually delivers its promised output and charges the correct amount. It is the right choice for buyers performing due diligence before committing to large or repeated purchases, and for sellers who want to generate verifiable proof of their endpoint's functionality for marketplace listings. It is distinct from static safety checks or diagnostic tools — it actually executes a real payment and validates the result end-to-end.
Side effects
- Endpoint price exceeds $0.1 USDC cap — check rejected as too expensive to test
- Target endpoint is not reachable or returns non-402 errors — delivery check fails with connectivity error
- Target endpoint's response does not match its declared output schema — reported as delivery failure
- On-chain charge cannot be measured or differs from advertised price — reported as discrepancy
- Job result not yet available — caller must poll later using the returned job ID
- Target endpoint only accepts POST — must specify method=POST in query params
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"id": "k3v9x2m7qa",
"eta": "usually within 30 minutes",
"url": "https://rest.coincap.io/v3/agentFriendly/full_assets_by_slug",
"method": null,
"status": "queued",
"queued_at": "2026-10-12T17:00:00.000Z",
"status_url": "https://x402-doctor.fizzl.eu/api/v1/delivery-check/k3v9x2m7qa",
"endpoint_price_usd": 0.002
}
}Tags
x402
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