x402 preflight
x402 preflight: checks a paid x402 endpoint before a payment is signed. Probes it unpaid, parses the v1 body or v2 PAYMENT-REQUIRED header, lints every accepts[] option (network, canonical USDC, EIP-712 domain name/version that signatures verify against, EIP-55 payTo, zero payTo, amount, timeout, testnet, resource host) and returns ok/warn/block with reasons. Input: URL, optionally 'POST <url>'. Deterministic, no LLM.
Answeringour last check, 2026-11-04
5 of 5checks answered this week
177 msmedian answer time
$0.005listed price per call
$0.005price 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
POST https://minty-sprout.onrender.com/v1/x402-preflight
| Category | Everything else |
|---|---|
| Provider host | minty-sprout.onrender.com |
| Networks | eip155:8453 |
| Payment schemes | exact |
| Self-reported calls, 30 days | 1 from 1 payers (the provider's figure, not ours) |
Our checks, last 30 days
| Day | Result | HTTP | Asked | Time |
|---|---|---|---|---|
| 2026-11-04 | valid payment request | 402 | $0.005 | 180 ms |
| 2026-11-03 | valid payment request | 402 | $0.005 | 172 ms |
| 2026-11-02 | valid payment request | 402 | $0.005 | 171 ms |
| 2026-11-01 | valid payment request | 402 | $0.005 | 177 ms |
| 2026-10-31 | valid payment request | 402 | $0.005 | 180 ms |
Example input (from the provider)
{
"body": {
"input": "https://x402-preflight.nextill-pos.workers.dev/v1/preflight"
},
"bodyType": "json",
"method": "POST",
"type": "http"
}
Promised output schema (from the provider)
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"input": {
"additionalProperties": false,
"properties": {
"body": {
"properties": {
"input": {
"maxLength": 8000,
"type": "string"
}
},
"required": [
"input"
],
"type": "object"
},
"bodyType": {
"enum": [
"json",
"form-data",
"text"
],
"type": "string"
},
"method": {
"enum": [
"POST"
],
"type": "string"
},
"type": {
"const": "http",
"type": "string"
}
},
"required": [
"type",
"method",
"bodyType",
"body"
],
"type": "object"
},
"output": {
"properties": {
"example": {
"properties": {
"issues": {
"type": "array"
},
"latency_ms": {
"type": "integer"
},
"options": {
"type": "array"
},
"status": {
"type": "integer"
},
"verdict": {
"enum": [
"ok",
"warn",
"block"
]
},
"x402_version": {
"type": [
"integer",
"null"
]
}
},
"type": "object"
},
"type": {
"type": "string"
}
},
"required": [
"type"
],
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
}