URL Freshness Check

x402

URL Freshness Check is a paid API for AI agents from defi-shield-hazel.vercel.app, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-11, last successful call 2026-04-20).

Performs a real HTTP fetch of a URL and analyzes cache headers, staleness, ETag, and response time to determine if the resource is fresh or stale.

Price / call$0.01

Seller volume →—

Success100%

StatusUnknown

Output

Returns a JSON object with the target URL's reachability status, HTTP status code, freshness_status (fresh/stale), age_seconds, cache_control directives, cache_max_age, ETag, last_modified, response_time_ms, content_type, server, an array of freshness_signals supporting the determination, and an array of staleness_reasons if applicable, plus the timestamp it was analyzed.

Example use cases

Example prompt

“Can you check if https://api.coingecko.com/api/v3/simple/price?ids=bitcoin&vs_currencies=usd is returning fresh data right now — I want to know if the response is stale, what its cache age is, and whether it's actually reachable?”

Technical details

Endpoint

POSThttps://defi-shield-hazel.vercel.app/api/safety/freshness-check?utm_source=zero.xyz

When to prefer

Use this endpoint when you need to programmatically verify whether a specific URL is serving fresh or stale content based on real HTTP cache headers, rather than relying on static assumptions. Ideal for monitoring data pipelines, validating third-party API freshness before consuming their data, or checking whether a CDN or cache layer is behaving correctly. Prefer this over simple availability checks when cache semantics (max-age, ETag, must-revalidate) matter for your use case.

Side effects

URL is unreachable or returns a network error — reachable: false with no cache data
Request to target URL times out after 5 seconds — timeout error returned
Target URL returns a non-200 status code — status_code reflects the error, freshness may be undetermined
Malformed or missing URL input — validation error response
Target URL blocks the checker's IP or returns a captcha/403

Input

{
  "input": {
    "body": {
      "url": "https://api.coingecko.com/api/v3/simple/price?ids=ethereum&vs_currencies=usd"
    },
    "type": "http",
    "method": "POST",
    "bodyType": "json"
  }
}

Output

{
  "url": "https://api.coingecko.com/api/v3/simple/price?ids=ethereum&vs_currencies=usd",
  "etag": "W/\"b9d16f0a6ff7657986295516e1f1eb36\"",
  "stale": true,
  "server": "cloudflare",
  "reachable": true,
  "age_seconds": 33,
  "analyzed_at": "2026-06-12T02:04:03.831Z",
  "status_code": 200,
  "content_type": "application/json; charset=utf-8",
  "cache_control": "max-age=30, public, must-revalidate, s-maxage=60",
  "cache_max_age": 30,
  "last_modified": null,
  "content_length": null,
  "freshness_status": "stale",
  "response_time_ms": 42,
  "freshness_signals": [
    "Cache-Control: max-age=30, public, must-revalidate, s-maxage=60",
    "must-revalidate directive present",
    "ETag present: W/\"b9d16f0a6ff7657986295516e1f..."
  ],
  "staleness_reasons": [
    "Age (33s) exceeds max-age (30s)"
  ],
  "last_modified_age_seconds": null
}

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