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x402 Payment Challenge & Payload Conformance Linter
x402
x402 Payment Challenge & Payload Conformance Linter is a paid API for AI agents from agents.daedalusdevelopmentgroup.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-20).
Statically validates x402 v2 payment challenges and signed paymentPayload objects against the full protocol spec, returning a signed verdict with exact per-failure remediations — no network fetch required.
Price / call$0.01
Success—
StatusUnknown
How this service works
Static conformance lint of an x402 v2 402 challenge and/or a signed paymentPayload: version, resource URL/description cliff, accepts scheme/network/asset/atomic-amount/timeout/payTo, EIP-712 token metadata, bazaar extension shape, PAYMENT-REQUIRED header decodability, header-version mismatch, and payload authorization/nonce/expiry. Returns a signed conformant verdict with an exact remediation per failure. No network fetch.
Output
A signed conformance verdict indicating whether the submitted x402 challenge and/or paymentPayload passes validation, plus a structured list of every failure with an exact, field-level remediation instruction for each. No network calls are made; all checks are purely static.
Example use cases
Debug a rejected x402 payment header
“My x402 payment header keeps getting rejected and I don't know why — can you lint the 402 challenge and paymentPayload I'm sending and give me the exact field-level errors and what to fix?”
Pre-flight check before deploying a payable API
“Before I ship my new agent-payable endpoint, can you validate my x402 v2 402-challenge object to make sure the accepts scheme, network, asset, atomic-amount, timeout, and payTo fields all pass the spec?”
Catch header-version mismatch in x402 integration
“I think I have a version mismatch between my PAYMENT-REQUIRED header and my paymentPayload — can you run a conformance lint on both and tell me if there's a mismatch and how to resolve it?”
Technical details
Endpoint
POSThttps://agents.daedalusdevelopmentgroup.com/v1/x402/402-lint?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need a fast, offline, static conformance check of an x402 v2 payment challenge or signed paymentPayload without making any network requests. It is ideal for pre-deployment validation, CI/CD lint steps, or debugging rejected payments when you need exact per-field remediations rather than a generic error. Prefer it over manual spec-reading or live facilitator round-trips when you need deterministic, signed verdicts you can act on immediately.
Side effects
- Missing required fields in the 402 challenge object returns specific field-level errors
- Invalid or unsupported accepts scheme/network/asset combination flagged as non-conformant
- EIP-712 metadata shape mismatch returned with remediation
- Header-version mismatch between PAYMENT-REQUIRED header and payload body flagged explicitly
- Expired or missing nonce/expiry in paymentPayload returned as authorization failure
- Malformed resource URL or description exceeding cliff limits returned with remediation
- Bazaar extension shape violations returned as separate failure entries
- Request body missing required 'input' or 'output' wrapper returns 400-level error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| outputrequired | object |
Tags
x402
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