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x402 Payment Preflight Checker
x402
x402 Payment Preflight Checker is a paid API for AI agents from anibalb.duckdns.org, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-31).
Checks whether a given HTTP endpoint is properly configured to accept x402 micropayments and returns a diagnostic verdict with payment details
Price / call$0.005
Success—
StatusUnknown
How this service works
Public data and utility APIs paid per call in USDC on Base (x402). No accounts, no API keys. 174 routes: crypto/equity data, onchain reads, DNS/email/security intel, geo/weather, x402 payment diagnostics, dev utilities and more.
Output
Returns a JSON object with the target URL, a compliance score (0-100), an array of named diagnostic checks (each with pass/fail status), the HTTP status code received, accepted payment terms (amount, network, USD price, checksum validity), a boolean payability flag, and an overall verdict string (e.g. 'payable').
Example use cases
Debugging a misconfigured x402 API
“My x402 endpoint doesn't seem to be accepting payments correctly — can you run a preflight diagnostic on it using a GET request and tell me which checks are failing and what the verdict is?”
Pre-call payability check for an agent
“Before my agent tries to pay and call that endpoint, can you do a preflight check with a GET to confirm it's actually payable and find out the exact USDC amount and wallet address it expects on Base?”
Auditing a new x402-enabled route
“I just added a new paid route to my API — can you run an x402 preflight on it via GET to verify it returns a proper 402 status, passes all compliance checks, and has a valid payTo address?”
Technical details
Endpoint
GEThttps://anibalb.duckdns.org/x402/x402-payment-preflight?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need to programmatically verify that an x402-gated API endpoint is correctly configured before attempting a micropayment — ideal for agent pre-flight logic, developer debugging, or automated compliance audits of x402 routes. Prefer this over manually inspecting 402 headers when you want a structured, scored diagnostic report.
Side effects
- Target endpoint is unreachable or times out — checks array will reflect failed connectivity
- Endpoint does not return a 402 status — returns_402 check will fail and verdict will be non-payable
- Malformed payment header on target — payTo_checksum_ok will be false
- Invalid or unsupported HTTP method supplied — request rejected by schema validation
- Target endpoint is on an unsupported network — accepts array may be empty
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"url": "https://example.com/api",
"score": 100,
"checks": [
{
"ok": true,
"name": "returns_402"
}
],
"status": 402,
"accepts": [
{
"amount": "1000",
"network": "eip155:8453",
"price_usd": 0.001,
"payTo_checksum_ok": true
}
],
"payable": true,
"verdict": "payable"
}
}Tags
x402
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