# offercheck URL Liveness & Metadata Checker

> offercheck URL Liveness & Metadata Checker is a paid API for AI agents from offercheck.offercheck.workers.dev, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-11).

Checks a public URL for liveness, redirect chain, domain age, robots policy, archive availability, and soft-404 status

## Facts

- Endpoint: GET https://offercheck.offercheck.workers.dev/v1/check/url?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/offercheck-url-liveness-metadata-checker-4087272b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_aOZiZOZA2q_2CMS_yKByN

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 offercheck-url-liveness-metadata-checker-4087272b
```

Example prompt: Can you check if https://example.com/docs/page is actually live, see if it redirects anywhere, how old the domain is, and whether it allows bots like GPTBot to crawl it?

## When to prefer this

Choose this endpoint when you need to verify a URL's health and metadata before taking action on it — such as before scraping, linking, or indexing. It is especially valuable for checking bot accessibility (robots policy per agent), detecting soft-404s, validating domain age and registrar trust, and checking Wayback Machine archive status. Prefer it over a generic HTTP HEAD check when you need the full picture: domain provenance, redirect chain, archive history, and per-bot crawlability in a single pay-per-call request with no API key required.

## Known failure modes

- URL is unreachable or DNS fails — alive:false returned with no HTTP status
- Private or intranet URLs return connection errors
- Malformed URL input causes 400 validation error
- Robots.txt not fetchable — robots.fetched:false with empty agents
- Archive not available for the URL — archive.available:false
- Payment not provided or insufficient — 402 Payment Required
- Rate limiting or upstream timeout — may return partial data with warnings

## How this service works

Check a URL before you cite, visit or trust it: liveness, final URL and redirect chain, soft-404 detection, page title, domain registration age (RDAP), robots.txt policy for AI agents, and Wayback Machine snapshot availability. $0.002 per check.

## Output

Returns a JSON object with: liveness flag, HTTP status code, response time in ms, final URL after redirects, full redirect chain with statuses, HTTPS flag, page title, content type, response size in bytes, domain RDAP info (registrar, registration date, age in days), robots.txt policy per bot agent, Wayback Machine archive availability and closest snapshot URL, soft-404 detection flag, confidence score (0–1), warnings array, and timestamp of 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",
       "format": "uri",
       "description": "Any public http/https URL"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ms": 950,
  "url": "https://example.com/docs/page",
  "alive": true,
  "bytes": 15321,
  "https": true,
  "title": "Docs — Page",
  "domain": {
   "name": "example.com",
   "rdap_ok": true,
   "age_days": 11365,
   "registrar": "RESERVED-Internet Assigned Numbers Authority",
   "registered_at": "1995-08-14T04:00:00Z"
  },
  "robots": {
   "agents": {
    "*": true,
    "GPTBot": true,
    "ClaudeBot": true
   },
   "fetched": true
  },
  "archive": {
   "available": true,
   "closest_url": "http://web.archive.org/web/20260901000000/https://example.com/docs/page",
   "closest_timestamp": "20260901000000"
  },
  "soft_404": false,
  "warnings": [],
  "final_url": "https://example.com/docs/page",
  "checked_at": "2026-09-25T20:00:00.000Z",
  "confidence": 0.9,
  "http_status": 200,
  "content_type": "text/html; charset=utf-8",
  "redirect_chain": [
   {
    "url": "https://example.com/docs/page",
    "status": 200
   }
  ]
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/offercheck-url-liveness-metadata-checker-4087272b/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from offercheck.offercheck.workers.dev](https://www.zero.xyz/host/offercheck.offercheck.workers.dev/llms.txt)