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x402 Invoice Decode & Validator
x402
x402 Invoice Decode & Validator is a paid API for AI agents from x402-research-iota.vercel.app, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-30).
Decodes and validates a base64-encoded x402 PAYMENT-REQUIRED header, returning a structured analysis of payment requirements including asset, network, amount, scheme, and overall verdict.
Price / call$0.02
Success—
StatusUnknown
How this service works
Use before paying any x402 invoice: decodes a base64 PAYMENT-REQUIRED header (query ?header= or JSON body {header}) and checks scheme exact, Base mainnet, Base USDC asset, payTo (EOA/contract/EIP-7702), human amount, timeout; returns verdict ok/warn/fail with reasons. Errors: 400 invalid header. Read-only; never signs or pays.
Output
Returns a JSON object with the decoded x402 payment details: a top-level verdict (ok/warn/fail), an array of accepted payment options (each with asset contract address, payTo EOA address, amount, amount in USDC, network chain ID, scheme, max timeout, and per-check results), a reasons array for any warnings or failures, the resource URL the payment unlocks, and the x402 protocol version.
Example use cases
Debug a failing x402 payment flow
“I'm getting a 402 response from an API and my payment isn't going through — can you decode the PAYMENT-REQUIRED header and tell me if it's valid, what the verdict is, and which address and amount it expects? The base64 header is eyJ4NDAyVmVyc2lvbiI6Mn0=”
Verify x402 header before paying
“Before I send any USDC, decode this x402 invoice header and confirm it's legitimate — check the verdict, the network, and that the amount is reasonable. Header: eyJhY2NlcHRzIjpbXX0=”
Inspect payment requirements of an x402 API
“I want to integrate with an x402-gated API endpoint — can you parse the base64 payment header it returned and break down the asset, payTo address, scheme, timeout, and overall ok/warn/fail verdict for me? Header value is eyJ4NDAyVmVyc2lvbiI6Mn0=”
Technical details
Endpoint
GEThttps://x402-research-iota.vercel.app/api/x402/invoice-decode?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need to programmatically inspect or validate an x402 PAYMENT-REQUIRED header before deciding whether to proceed with payment — especially useful for debugging integration issues, auditing payment requirements, or building x402-aware agent pipelines that need to parse payment terms without making the actual payment.
Side effects
- Missing or malformed 'header' query parameter returns an error or empty result
- Invalid base64 input causes a decode failure
- Well-formed base64 but non-x402 payload produces a fail verdict
- Network issues to the decoder service return a 5xx error
- Unsupported x402 version may return a warn or fail verdict
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"signed": false,
"accepts": [
{
"asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"payTo": {
"kind": "eoa",
"address": "0xa26f...8147"
},
"amount": "100000",
"checks": [
{
"check": "scheme",
"level": "ok",
"detail": "scheme=exact"
}
],
"scheme": "exact",
"network": "eip155:8453",
"verdict": "ok",
"amountUsdc": 0.1,
"maxTimeoutSeconds": 300
}
],
"reasons": [],
"verdict": "ok",
"resource": {
"url": "https://x402-research-iota.vercel.app/api/firm/risk-snapshot"
},
"x402Version": 2
}
}Tags
x402
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