# Fetchgate x402 Endpoint Checker

> Fetchgate x402 Endpoint Checker is a paid API for AI agents from fetchgate.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-10).

Validates whether a given URL is a well-formed, functioning x402 payment-gated endpoint by checking its challenge response.

## Facts

- Endpoint: GET https://fetchgate.dev/v1/x402/check?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-10
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/fetchgate-x402-endpoint-checker-11e006a5
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_mOZMCWjutKbo3tFZ-BhBQ

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 fetchgate-x402-endpoint-checker-11e006a5
```

Example prompt: Can you check whether https://api.example.com/v1/resource is a properly configured x402 endpoint — I want to know if it returns a valid payment challenge before I try paying for it.

## When to prefer this

Use this endpoint when you need to verify that a specific URL is correctly implementing the x402 micropayment protocol before committing to a payment flow. It is the right choice when debugging x402 integration issues, auditing third-party payment-gated APIs, or pre-checking an endpoint's conformance before building an automated payment agent on top of it.

## Known failure modes

- URL is not reachable — network error or timeout
- Target URL does not return an HTTP 402 response at all — verdict is not 'ok'
- Invalid or malformed URL provided in query params
- x402 challenge response is present but malformed — reasons array explains specific issues
- Method not in allowed enum (GET, HEAD, DELETE) — validation error

## How this service works

Should an agent pay this x402 endpoint? One live probe of its payment challenge plus its settled-call and unique-payer history, price consistency and domain reputation, returned as ok / caution / avoid with reasons. Use before paying an unfamiliar x402 endpoint.

## Output

Returns a JSON object with the checked URL, a verdict ('ok' or failure status), and an array of human-readable reasons explaining why the endpoint does or does not conform to the x402 standard.

## 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",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "url"
     ],
     "properties": {
      "url": {
       "type": "string",
       "description": "The x402 endpoint URL to check."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "url": "https://api.example.com/v1/resource",
  "reasons": [
   "Returns a well-formed x402 challenge."
  ],
  "verdict": "ok"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/fetchgate-x402-endpoint-checker-11e006a5/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from fetchgate.dev](https://www.zero.xyz/host/fetchgate.dev/llms.txt)