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x402 Readiness Checker
x402
x402 Readiness Checker is a paid API for AI agents from agents.crowdspark.me, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-31).
Probes a paid API URL without paying to verify it correctly implements the x402 payment protocol and reports a readiness score with specific issues.
Price / call$0.005
Success—
StatusUnknown
How this service works
Pay-per-call utilities for AI agents over x402, USDC on Base.
Output
Returns a JSON object with: the probed URL, probe timing and HTTP status, a boolean ready flag, a 0-100 compliance score, a list of specific issues (or empty if compliant), an accepts array detailing payment requirements (payTo, scheme, network, price_usd, asset_symbol, amount_atomic, max_timeout_seconds), verdict string ('ready' or 'needs_fixes'), x402 version detected, delivery method (header or body), x402_detected boolean, and Bazaar discovery status.
Example use cases
Pre-listing compliance check
“Before I submit my API to agentic.market, can you run an x402 readiness check on https://mypaidapi.io/v1/query and tell me if anything needs fixing?”
Debugging a failed 402 implementation
“My API at https://api.myproject.dev/data is supposed to require x402 payment but agents can't pay it — can you probe it and tell me exactly what's wrong with the 402 response?”
Verifying a third-party paid endpoint before use
“Before I integrate https://external-service.com/v1/results into my agent, can you check if it's a valid x402 endpoint and confirm the price, network, and payTo address look correct?”
Technical details
Endpoint
GEThttps://agents.crowdspark.me/v1/x402/check?utm_source=zero.xyzWhen to prefer
Use this endpoint whenever you need to verify an API correctly implements the x402 payment protocol before paying it, listing it on a marketplace, or integrating it into an agent workflow. It never actually sends payment, making it safe to run repeatedly. Prefer it over manual inspection when you need a structured score, EIP-55 checksum validation, and Bazaar discovery verification in a single call.
Side effects
- Target URL is unreachable or times out — probe reports connection failure
- Target URL returns non-402 status and is not x402 — x402_detected false, score 0
- payTo address fails EIP-55 checksum — reported as specific issue in issues list
- Missing required fields in 402 response — each missing field listed as a separate issue
- Malformed EIP-712 domain — flagged in issues with details
- Score below 100 with non-empty issues array when implementation is partially compliant
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"url": "https://api.example.com/v1/data",
"probe": {
"ms": 312,
"method": "GET",
"status": 402,
"redirects": 0
},
"ready": true,
"score": 100,
"issues": [],
"accepts": [
{
"pay_to": "0x0dEA0030A17BF886543a757c55924710258c2eec",
"scheme": "exact",
"network": "eip155:8453",
"price_usd": 0.001,
"asset_symbol": "USDC",
"amount_atomic": "1000",
"max_timeout_seconds": 300
}
],
"verdict": "ready",
"version": 2,
"discovery": {
"bazaar": true
},
"delivered_via": "PAYMENT-REQUIRED header",
"x402_detected": true
}
}Tags
x402
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