Validate an x402 payment declaration before signing
Validate an x402 payment declaration before signing. Check a caller-supplied challenge against expected resource, network, asset, payee and exact spending limits; return mismatches and an integrity receipt. Offline only: no endpoint probe, uptime history, settlement test, safety clearance or payment authorization. New modular adapter: retained result recovery for 24 hours, minimal receipt metadata for 90 days. Existing live route unchanged.
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://www.mahastrategies.com/api/v1/verify/payments/challenge-sanity
| Category | Everything else |
|---|---|
| Provider host | www.mahastrategies.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 |
|---|---|---|---|---|
| 2026-10-18 | no x402 terms | 429 | 16 ms |
Example input (from the provider)
{
"body": {
"challenge": {
"amountBaseUnits": "10000",
"asset": "0x1111111111111111111111111111111111111111",
"maxTimeoutSeconds": 60,
"network": "eip155:8453",
"payee": "0x1111111111111111111111111111111111111111",
"resourceUrl": "https://example.org/result",
"scheme": "exact",
"version": 2
},
"dataClass": "synthetic",
"expected": {
"asset": "0x1111111111111111111111111111111111111111",
"maxAmountBaseUnits": "10000",
"network": "eip155:8453",
"payee": "0x1111111111111111111111111111111111111111",
"resourceUrl": "https://example.org/result"
}
},
"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": {
"additionalProperties": false,
"properties": {
"challenge": {
"type": "object"
},
"dataClass": {
"enum": [
"public",
"synthetic"
],
"type": "string"
},
"expected": {
"type": "object"
}
},
"required": [
"dataClass",
"expected",
"challenge"
],
"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": {
"additionalProperties": false,
"properties": {
"data": {
"type": "object"
},
"proof": {
"type": "object"
},
"success": {
"const": true
}
},
"required": [
"success",
"data",
"proof"
],
"type": "object"
},
"type": {
"type": "string"
}
},
"required": [
"type"
],
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
}