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x402 Trust Attestation API
x402
x402 Trust Attestation API is a paid API for AI agents from x402-url-evidence.vercel.app, paid per call via x402, $0.05/call, status unknown (last checked 2026-09-15).
Validates and attests the trustworthiness of an x402 payment-gated HTTPS endpoint by checking its protocol readiness, payment terms, and fingerprint integrity.
Price / call$0.05
Success—
StatusUnknown
How this service works
Paid deterministic utility APIs settled in native USDC on Base.
Output
Returns a JSON object containing: a boolean 'safeToPay' flag, a 'verdict' string (e.g. 'ready'), a 'protocol' object with x402 version and readiness, an 'attestation' object with SHA-256 fingerprint and a 'changed' boolean indicating drift from a prior baseline, a summary of passed/failed/warning checks, and an optional 'receipt' for transaction hash verification.
Example use cases
Pre-flight check before USDC payment
“Before my agent pays into https://api.someservice.xyz/results, can you attest that it's a legitimate x402 endpoint expecting USDC on Base at address 0xDEF...789? I want to confirm it's safe to pay and get a fingerprint I can use next time.”
Detect tampered payment terms
“Last week I got a fingerprint 'f4e3d2c1b0a9...8765' for the x402 endpoint at https://data.provider.io/feed — can you re-attest it now and tell me if anything has changed in the payment terms?”
Audit new third-party x402 service
“I'm evaluating a third-party x402 API at https://vendor.app/api/premium — it should be a POST endpoint paid to 0xAAA...BBB in USDC on Base. Can you run a full trust attestation and tell me whether the protocol is ready and how many checks passed?”
Technical details
Endpoint
POSThttps://x402-url-evidence.vercel.app/api/x402-trust-attestationWhen to prefer
Use this endpoint when an AI agent needs to verify the integrity and payment parameters of an x402-gated API before committing USDC. It is the right choice when you want a deterministic, reproducible fingerprint of an endpoint's payment terms, when you need to detect drift between two calls (e.g. was the payTo address swapped?), or when onboarding a new third-party x402 service and need a safety audit. Prefer this over manual inspection when trust verification needs to be automated, auditable, and settled without human review.
Side effects
- Endpoint URL is not reachable or returns non-x402 headers — verdict will indicate not ready
- Payment terms mismatch expected values (wrong asset, payTo, or network) — warnings or failures in summary
- Receipt transaction hash does not match current payment terms — attestation flags discrepancy
- Baseline fingerprint differs from current state — 'changed: true' returned, safeToPay may be false
- Malformed or non-HTTPS URL provided — validation error on input schema
- x402 protocol version incompatibility — protocol.ready returns false
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| url | string | Credential-free public HTTPS x402 endpoint |
| method | string | |
| expected | object | |
| receiptTxHash | string | Optional Base transaction hash to verify against current terms |
| baselineFingerprint | string | Optional prior SHA-256 attestation fingerprint |
Output
Schema · Response
{
"type": "json",
"example": {
"receipt": null,
"summary": {
"failed": 0,
"passed": 15,
"warnings": 0
},
"verdict": "ready",
"protocol": {
"ready": true,
"x402Version": 2
},
"safeToPay": true,
"attestation": {
"changed": false,
"algorithm": "sha256",
"fingerprint": "64-character digest"
}
}
}Tags
x402
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