Broken Link Checker

Fetch a webpage, extract a[href] links, and probe each URL's HTTP status from Cloudflare's edge.

Features

• Extracts absolute and same-origin relative links from HTML
• Probes up to 25 links by default (max 50) with HEAD, falling back to GET
• Runs probes concurrently (5 at a time) with per-link timeouts
• Stateless; no bindings required

API Reference

GET /check

Example Request

curl "https://your-worker.workers.dev/check?url=https://www.cloudflare.com&limit=10"

Success Response

url string

Final page URL after redirects

checked number

Number of links probed

broken number

Count of non-OK responses

links array

Per-link { href, statusCode, ok, error? }

{
  "url": "https://www.cloudflare.com/",
  "checked": 10,
  "broken": 1,
  "links": [
    { "href": "https://www.cloudflare.com/", "statusCode": 200, "ok": true },
    { "href": "https://www.cloudflare.com/missing", "statusCode": 404, "ok": false }
  ]
}

Error Codes

• 400 - Missing or invalid url (INVALID_URL)
• 400 - Response was not HTML (NOT_HTML)
• 502 - Page fetch failed (FETCH_ERROR)

Use Cases

• Find dead links before publishing content
• Spot-check navigation and footer URLs
• Complement link extraction tools with live status checks
• Build simple site QA workflows on Workers

Limitations

• Does not execute JavaScript; only links present in raw HTML
• Caps probes (default 25) to stay under Worker time limits
• Some origins block HEAD or bots; status codes may reflect bot filtering

Deployment

curl "https://your-worker.workers.dev/check?url=https://example.com"

Local Development

cd apps/experiments/broken-link-checker
npm install
npm run dev

curl "http://localhost:8787/check?url=https://www.cloudflare.com"

Cloudflare Features Used

• Workers - Edge compute runtime
• Fetch API - Page fetch and link probes

Next Steps