Use before paying any x402 invoice
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.
Answers HTTP 400 without x402 payment termsour last check, 2026-10-25
0 of 1checks answered this week
n/amedian answer time
$0.02listed price per call
n/aprice it asked us
Paid test badge: not yet. The checks above are free: we call the tool without paying and read the payment request it sends back. The Verified badge needs paid calls whose answers match the promised output, and nobody can buy a badge.
Endpoint
GET https://x402-research-iota.vercel.app/api/x402/invoice-decode
| Category | Search and research |
|---|---|
| Provider host | x402-research-iota.vercel.app |
| Networks | eip155:8453 |
| Payment schemes | exact |
| Self-reported calls, 30 days | 0 from 0 payers (the provider's figure, not ours) |
Our checks, last 30 days
| Day | Result | HTTP | Asked | Time |
|---|---|---|---|---|
| 2026-10-25 | no x402 terms | 400 | 516 ms |
Example input (from the provider)
{
"method": "GET",
"queryParams": {
"header": "eyJ4NDAyVmVyc2lvbiI6Miwi..."
},
"type": "http"
}
Promised output schema (from the provider)
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"input": {
"additionalProperties": false,
"properties": {
"method": {
"enum": [
"GET"
],
"type": "string"
},
"queryParams": {
"properties": {
"header": {
"description": "base64 PAYMENT-REQUIRED header value",
"type": "string"
}
},
"required": [
"header"
],
"type": "object"
},
"type": {
"const": "http",
"type": "string"
}
},
"required": [
"type",
"method"
],
"type": "object"
},
"output": {
"properties": {
"example": {
"properties": {
"accepts": {
"items": {
"type": "object"
},
"type": "array"
},
"reasons": {
"items": {
"type": "string"
},
"type": "array"
},
"resource": {
"type": "object"
},
"signed": {
"type": "boolean"
},
"verdict": {
"enum": [
"ok",
"warn",
"fail"
],
"type": "string"
},
"x402Version": {
"type": "number"
}
},
"type": "object"
},
"type": {
"type": "string"
}
},
"required": [
"type"
],
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
}