Response Headers

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

API Endpoint

GET /headers

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

url string (required)

The target URL (must be http or https)

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

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