Response Headers

Fetch any URL and return its HTTP status and response headers as JSON.

API Reference

GET /headers

Uses HEAD first and falls back to GET when the origin does not support HEAD.

Example Request

curl "https://your-worker.workers.dev/headers?url=https://www.cloudflare.com"

Success Response

url string

Final URL after redirects

statusCode number

HTTP status code

statusText string

HTTP status text

method string

HEAD or GET

headers object

Response headers as key/value pairs

{
  "url": "https://www.cloudflare.com/",
  "statusCode": 200,
  "statusText": "OK",
  "method": "HEAD",
  "headers": {
    "content-type": "text/html; charset=utf-8",
    "server": "cloudflare"
  }
}

Error Codes

• 400 - Missing or invalid url (INVALID_URL)
• 502 - Fetch failed (FETCH_ERROR)

Use Cases

• Debug cache and security headers from the edge
• Compare response headers across origins
• Learn HEAD vs GET fallback patterns in Workers

Limitations

• Uses HEAD with GET fallback; some origins return different headers per method
• Single URL per request
• Fetch timeout on slow origins

Deployment

curl "https://your-worker.workers.dev/headers?url=https://www.cloudflare.com"

Local Development

cd apps/experiments/response-headers
npm install
npm run dev

Cloudflare Features Used

• Workers - Edge compute runtime
• Fetch API - HTTP requests from the edge