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Keystone Opportunity API – x402 Conformance Probe
x402
Keystone Opportunity API – x402 Conformance Probe is a paid API for AI agents from keystone-opportunity-api.keystone-opportunity.workers.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-14).
Validates a live x402-protected URL by probing its HTTP 402 challenge, v2 payment schema, Base USDC amount, payTo/network fields, and OpenAPI price consistency — without making a payment.
Price / call$0.01
Success—
StatusUnknown
How this service works
Probe an x402 URL without paying it: validate the live HTTP 402 challenge, v2 payment schema, Base USDC amount, payTo/network fields, and OpenAPI-to-live price consistency.
Output
Returns a structured conformance report indicating whether the target URL correctly returns an HTTP 402 challenge, whether the payment schema matches the v2 specification, whether the Base USDC amount is present and valid, whether the payTo and network fields are correctly set, and whether the live price is consistent with the OpenAPI document.
Example use cases
Pre-integration x402 compliance check
“Before I integrate this payment-gated API into my app, can you probe https://api.myservice.com/data using a GET request and confirm it's fully x402 compliant — valid 402 challenge, correct v2 schema, and that the Base USDC amount matches what the OpenAPI docs say?”
Debug misconfigured x402 payment endpoint
“My x402 endpoint at https://myapi.dev/protected is rejecting agents even though I set it up correctly — can you probe it and tell me exactly which fields are wrong or missing, like the payTo address, network, or schema version?”
CI/CD x402 conformance gate
“As part of my deployment check, validate that https://staging.myplatform.io/api/resource returns a proper HTTP 402 challenge with a valid v2 payment schema and that the live price matches the OpenAPI spec at https://staging.myplatform.io/openapi.json — without paying anything.”
Technical details
Endpoint
POSThttps://keystone-opportunity-api.keystone-opportunity.workers.dev/v1/x402/conformanceWhen to prefer
Use this endpoint when you need to verify that an x402-protected resource is correctly configured before integrating it, debugging payment failures, or running automated conformance checks in CI/CD pipelines. It is the right choice when you want to inspect the live 402 challenge and schema compliance without triggering an actual payment. Prefer this over manual inspection when you also need to cross-reference the live price against an OpenAPI specification.
Side effects
- Target URL does not return HTTP 402 (e.g. returns 200 or 404)
- x402 payment schema is version 1 or malformed instead of v2
- payTo or network fields are missing or incorrectly formatted
- OpenAPI document is unreachable or does not contain price information
- OpenAPI-to-live price mismatch detected
- Target URL is not publicly reachable or times out
- Non-HTTPS URL provided — only public HTTPS resources are supported
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| url | string | Public HTTPS x402 resource to probe without paying. |
| method | string | HTTP method used for the unpaid probe. Defaults to GET. |
| openapiUrl | string | Optional public HTTPS OpenAPI document. Defaults to /openapi.json on the target origin. |
Tags
x402
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