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agentbit.app x402 Endpoint & Payment Header Linter
x402
agentbit.app x402 Endpoint & Payment Header Linter is a paid API for AI agents from agentbit.app, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).
Validates x402 payment endpoints and payment headers against the v2 spec, catching EIP-712 domain name mismatches, CAIP-2 errors, expired authorizations, and Coinbase Bazaar indexing requirements.
Price / call$0.001
Success—
StatusUnknown
How this service works
Lint any x402 endpoint or payment header against the v2 spec and real CDP facilitator behavior: CAIP-2 network ids, atomic amounts, the EIP-712 domain-name trap ('USD Coin' on Base mainnet vs 'USDC' on Sepolia — wrong name = every settlement fails), the extensions echo Coinbase Bazaar requires for indexing, expired authorizations. Findings as error/warning/info with what will actually break. Built by a seller that debugged all of these in production.
Output
A JSON object containing a verdict (pass/fail), mode (live-probe or offline), per-category counts of errors/warnings/infos, a list of findings each with a code, severity level, and human-readable message explaining what will break and why, plus the HTTP status and number of accepted payment options.
Example use cases
Debug failing x402 settlements on Base
“My x402 payments keep failing on Base mainnet — can you probe https://myapi.example.com/data and tell me if the EIP-712 domain name is set correctly for USDC versus USD Coin, and what else might be broken?”
Validate offline PAYMENT-REQUIRED header
“I have a base64-encoded PAYMENT-REQUIRED header value from my x402 server — can you lint it offline and tell me if there are any spec violations or missing fields the Coinbase facilitator will reject?”
Check client payment payload before submission
“Before I send this x402 payment, can you validate my base64-encoded PAYMENT-SIGNATURE header value against the v2 spec and flag any errors like expired authorization or wrong atomic amounts?”
Technical details
Endpoint
POSThttps://agentbit.app/v1/x402/inspectWhen to prefer
Choose this endpoint when debugging x402 payment integrations, specifically for catching EIP-712 domain name mismatches ('USD Coin' vs 'USDC'), CAIP-2 network ID errors, Coinbase Bazaar indexing extension requirements, expired authorizations, or malformed payment headers. Prefer this over manual inspection when you need production-validated rules derived from real facilitator behavior, not just spec text.
Side effects
- Endpoint URL is unreachable or returns non-402 status — probe cannot complete
- Malformed base64 input for payment_payload or payment_required — parse error returned
- x402 endpoint times out — finding may be incomplete
- Network connectivity issues reaching the target URL
- No input provided (url, payment_payload, or payment_required required) — validation error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| url | string | A paid x402 endpoint to probe live (GET, expects the 402 envelope) |
| payment_payload | string | Base64 PAYMENT-SIGNATURE header value to lint the client payload (optionally alongside payment_required) |
| payment_required | string | Base64 PAYMENT-REQUIRED header value to lint offline |
Output
Schema · Response
{
"type": "json",
"example": {
"url": "https://agentbit.app/v1/web/search",
"mode": "live-probe",
"counts": {
"infos": 1,
"errors": 0,
"warnings": 0
},
"verdict": "pass",
"findings": [
{
"code": "EIP712_DOMAIN_OK",
"level": "info",
"message": "accepts[0]: extra.name matches USDC on Base mainnet."
}
],
"http_status": 402,
"accepts_count": 1
}
}Tags
x402
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