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SelectaRank x402 Preflight Checker
x402
SelectaRank x402 Preflight Checker is a paid API for AI agents from selectarank-data.vercel.app, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-02).
Checks whether a given HTTPS URL is protected by x402 and returns its payment requirements before attempting a paid call
Price / call$0.01
Success—
StatusUnknown
How this service works
Pay-per-call access to public-domain data (USGS earthquakes, NOAA/NWS forecasts, World Bank indicators) plus an x402 endpoint pre-payment checker over x402 on Base USDC. No account or API key.
Output
Returns a JSON object with the target URL, an array of accepted payment methods, a verdict string (e.g. 'ok'), the payment transport method (e.g. 'header'), and a boolean flag indicating whether the endpoint truly returns a 402 status. This lets callers understand payment requirements before committing funds.
Example use cases
Pre-call x402 payment discovery
“Can you check https://some-api.example.com/v1/data before I try to call it — I want to know if it needs x402 payment and what USDC options it accepts?”
Validate x402 endpoint configuration
“I just deployed my x402-protected API at https://myservice.vercel.app/v1/reports — can you do a preflight check to confirm it's correctly returning 402 and advertising its payment requirements?”
Agent workflow payment routing
“Before my agent tries to fetch data from https://selectarank-data.vercel.app/v1/worldbank, check whether it's x402-protected and what transport method it uses for payment, so I can wire up the right payment handler.”
Technical details
Endpoint
GEThttps://selectarank-data.vercel.app/v1/preflight?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need to programmatically discover whether a remote HTTPS endpoint requires x402 micropayment and what currencies/transport methods it accepts — especially before attempting an actual paid call. Prefer this over direct calling when you want to avoid unexpected payment failures or need to dynamically route payment logic in an agent workflow.
Side effects
- Non-HTTPS or non-port-443 URL returns a validation error
- Endpoint is not publicly reachable, resulting in a connection error
- URL is not x402-protected, returning isStatus402: false with an empty accepts array
- Malformed URL input causes a 400-level error
- Timeout if the target endpoint is slow to respond
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"url": "https://example.com/paid-endpoint",
"accepts": [],
"verdict": "ok",
"transport": "header",
"isStatus402": true
}
}Tags
x402
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