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Saylor Innovations x402 Endpoint Validator
x402
Saylor Innovations x402 Endpoint Validator is a paid API for AI agents from saylorinnovations.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-30).
Checks whether a given URL correctly returns a well-formed HTTP 402 payment-required challenge with valid network accepts per the x402 protocol
Price / call$0.01
Success—
StatusUnknown
How this service works
x402 endpoint validator - checks a URL returns a well-formed 402 challenge with valid accepts per network
Output
Returns a JSON object indicating whether the target URL is x402-compliant, including: a boolean found/compliant flag, HTTP status code returned, list of accepted blockchain networks, granular per-check results, any compliance issues found, response latency in milliseconds, the canonical URL checked, and the UTC timestamp of the check.
Example use cases
Pre-launch x402 compliance check
“I just built a paid API at https://myapp.com/api/premium-data and want to make sure it returns a proper x402 402 challenge before I list it publicly — can you verify it's compliant and show me any issues?”
Debugging broken payment gate
“My x402-gated endpoint at https://api.myservice.io/data/feed isn't being paid by agents correctly — can you run a compliance check on it and tell me what's wrong with the 402 response it returns?”
Auditing accepted networks on an endpoint
“Can you check what blockchain networks are listed as accepted in the 402 challenge from https://partner.example.com/api/report — I need to confirm it includes Polygon before we integrate with it?”
Technical details
Endpoint
GEThttps://saylorinnovations.com/api/x402check/verify?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need to programmatically verify that a URL correctly implements the x402 payment protocol — especially before listing an endpoint in a marketplace, integrating a third-party x402-gated API, or debugging 402 challenge formatting issues. It is specifically designed to surface x402 protocol compliance rather than general HTTP health or uptime.
Side effects
- Target URL is unreachable or times out — found: false with latency_ms null
- Target URL returns 200 or other non-402 status — x402_compliant: false with issues listing unexpected status
- 402 response is malformed or missing required fields — x402_compliant: false with detailed issues array
- No accepted_networks listed in the 402 response — issues flag missing network definitions
- Missing required query parameter 'url' — likely a 400 or validation error
- Rate limiting or cost — each call costs $0.01 USDC via x402
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Tags
x402
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