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Lumen x402 Header Lint & Decoder
x402
Lumen x402 Header Lint & Decoder is a paid API for AI agents from lumenworks-x402-decoder.onrender.com, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-11).
Decodes and lints x402 PAYMENT-REQUIRED, PAYMENT-SIGNATURE, or PAYMENT-RESPONSE headers (base64 or JSON), returning the header kind, decoded object, and any errors or warnings about CAIP-2, checksum, EIP-712 domain, or expiry.
Price / call$0.002
Success—
StatusUnknown
How this service works
Decode and lint an x402 PAYMENT-REQUIRED / PAYMENT-SIGNATURE / PAYMENT-RESPONSE header (base64 or JSON): kind, decoded object, errors/warnings (CAIP-2, checksum, EIP-712 domain, expiry).
Output
A JSON object with: ok (boolean indicating no critical errors), kind (PAYMENT-REQUIRED, PAYMENT-SIGNATURE, or PAYMENT-RESPONSE), decoded (the full parsed header object including accepts array, resource URL, x402Version, amounts, payTo address, network, scheme, and timeout), and issues (an array of errors and warnings covering CAIP-2 identifiers, address checksums, EIP-712 domain fields, and expiry status).
Example use cases
Debugging a malformed payment header
“I'm getting a weird x402 PAYMENT-REQUIRED header back from an API and I'm not sure if it's valid — can you decode it and tell me what's wrong with it? The raw base64 is eyJ4NDAyVmVyc2lvbiI6MiwiYWNjZXB0cyI6W119.”
Validating EIP-712 domain in a payment signature
“I just received a PAYMENT-SIGNATURE header and I want to make sure the EIP-712 domain and checksum look right before I accept it — here's the JSON: {"scheme":"exact","network":"eip155:8453","asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"}”
Checking x402 header expiry and CAIP-2 compliance
“Can you lint this x402 PAYMENT-RESPONSE header and let me know whether it's expired and whether the CAIP-2 network identifier is correct? Here's the value: eyJ4NDAyVmVyc2lvbiI6MiwidHlwZSI6InJlc3BvbnNlIn0=”
Technical details
Endpoint
POSThttps://lumenworks-x402-decoder.onrender.com/v1/x402/lint?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need to programmatically validate or debug an x402 HTTP payment header — especially when integrating x402-enabled APIs and want to catch CAIP-2 network mismatches, bad EIP-712 domains, invalid checksums, or expired payment requests before signing or submitting. Prefer this over manual inspection when the header is base64-encoded or when you need structured error reporting.
Side effects
- Invalid base64 input returns decode error
- Unrecognized header kind returns unknown type error
- Missing required fields in JSON body trigger validation errors in issues array
- Network connectivity issues to onrender.com hosting may cause 503 timeouts
- Malformed CAIP-2 network string flagged as error in issues but still returns decoded object
Output
Schema · Response
{
"type": "json",
"example": {
"ok": true,
"kind": "PAYMENT-REQUIRED",
"issues": [],
"decoded": {
"accepts": [
{
"asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"extra": {
"name": "USD Coin",
"version": "2"
},
"payTo": "0xee9790cB3960952F585379F831a89b4e00B4029A",
"amount": "2000",
"scheme": "exact",
"network": "eip155:8453",
"maxTimeoutSeconds": 120
}
],
"resource": {
"url": "https://lumenworks-x402-decoder.onrender.com/v1/tx/explain"
},
"x402Version": 2
}
}
}Tags
x402
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