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x402 Preflight URL Inspector
x402
x402 Preflight URL Inspector is a paid API for AI agents from solana-x402-microtools-mainnet.valecity.workers.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-29).
Probes a public HTTPS URL without following redirects and inspects whether it returns an x402 v2 payment-required challenge
Price / call$0.01
Success—
StatusUnknown
How this service works
Probe one public HTTPS URL without following redirects; inspect x402 v2 challenge
Output
Returns the target URL, HTTP status code, latency in milliseconds, a boolean indicating whether the URL serves an x402 v2 challenge, the payment terms object (or null if not x402), and the timestamp of the check.
Example use cases
Pre-call x402 payment discovery
“Before I try calling https://some-paid-api.com/endpoint, can you check if it requires an x402 payment and what the terms are, so I know what to expect?”
Verify x402 compliance of a new service
“I just deployed an x402-enabled API at https://myservice.valecity.workers.dev/api/data — can you probe it to confirm it's properly returning an x402 v2 challenge?”
Compare HTTP status and payment wall detection
“Can you hit https://content.example.com/premium without following any redirects and tell me the HTTP status, whether it's an x402 v2 endpoint, and how fast it responded?”
Technical details
Endpoint
GEThttps://solana-x402-microtools-mainnet.valecity.workers.dev/api/preflight?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need to determine programmatically whether a given HTTPS URL is protected by the x402 v2 micropayment protocol before attempting to call it, especially when building payment-aware agents or integrating with x402-gated APIs. Prefer it over generic HTTP HEAD tools when you specifically need x402 challenge parsing and structured payment terms extraction.
Side effects
- URL is not a valid HTTPS URI with a public DNS hostname — request rejected
- URL uses a custom port, URL credentials, or secret-bearing query parameters — request rejected
- Target host is unreachable or DNS fails — error returned
- Target returns a redirect chain but redirects are not followed — only first response inspected
- x402 terms present but malformed — is_x402_v2 may be false even if 402 status returned
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Tags
x402
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