# Saylor Innovations x402 Endpoint Validator

> Saylor Innovations x402 Endpoint Validator is a paid API for AI agents from saylorinnovations.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-30).

Checks whether a given URL correctly returns a well-formed HTTP 402 payment-required challenge with valid network accepts per the x402 protocol

## Facts

- Endpoint: GET https://saylorinnovations.com/api/x402check/verify?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-30
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/saylor-innovations-x402-endpoint-validator-8d1700d4
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_yuW1ZYeBOFLoofVS9xeQj

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability saylor-innovations-x402-endpoint-validator-8d1700d4
```

Example prompt: Can you check whether https://example.com/api/my-paid-resource is a properly configured x402 endpoint — does it return a valid 402 payment challenge with accepted networks?

## When to prefer this

Use this endpoint when you need to programmatically verify that a URL correctly implements the x402 payment protocol — especially before listing an endpoint in a marketplace, integrating a third-party x402-gated API, or debugging 402 challenge formatting issues. It is specifically designed to surface x402 protocol compliance rather than general HTTP health or uptime.

## Known failure modes

- Target URL is unreachable or times out — found: false with latency_ms null
- Target URL returns 200 or other non-402 status — x402_compliant: false with issues listing unexpected status
- 402 response is malformed or missing required fields — x402_compliant: false with detailed issues array
- No accepted_networks listed in the 402 response — issues flag missing network definitions
- Missing required query parameter 'url' — likely a 400 or validation error
- Rate limiting or cost — each call costs $0.01 USDC via x402

## How this service works

x402 endpoint validator - checks a URL returns a well-formed 402 challenge with valid accepts per network

## Output

Returns a JSON object indicating whether the target URL is x402-compliant, including: a boolean found/compliant flag, HTTP status code returned, list of accepted blockchain networks, granular per-check results, any compliance issues found, response latency in milliseconds, the canonical URL checked, and the UTC timestamp of the check.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "url"
     ],
     "properties": {
      "url": {
       "type": "string",
       "description": "the x402 resource URL to check (query)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "json"
    },
    "example": {
     "type": "object",
     "required": [
      "found"
     ],
     "properties": {
      "url": {
       "type": [
        "string",
        "null"
       ],
       "description": "Canonical URL"
      },
      "note": {
       "type": [
        "string",
        "null"
       ],
       "description": "Caveat or context for reading the result"
      },
      "found": {
       "type": "boolean",
       "description": "True when the lookup matched a record"
      },
      "checks": {
       "type": "object",
       "description": "Individual check results"
      },
      "issues": {
       "type": "array",
       "items": {
        "type": "string"
       },
       "description": "Issues found"
      },
      "checked_at": {
       "type": [
        "string",
        "null"
       ],
       "description": "Time the check was run (UTC)"
      },
      "latency_ms": {
       "type": [
        "number",
        "null"
       ],
       "description": "Response time in milliseconds"
      },
      "http_status": {
       "type": [
        "number",
        "null"
       ],
       "description": "HTTP status code returned"
      },
      "service_name": {
       "type": [
        "string",
        "null"
       ],
       "description": "Service name"
      },
      "x402_compliant": {
       "type": [
        "boolean",
        "null"
       ],
       "description": "X402 compliant"
      },
      "accepted_networks": {
       "type": [
        "array",
        "null"
       ],
       "description": "Accepted networks"
      }
     }
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/saylor-innovations-x402-endpoint-validator-8d1700d4/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from saylorinnovations.com](https://www.zero.xyz/host/saylorinnovations.com/llms.txt)