HTTP HEAD Request Errors — Response Header Mismatch and Implementation Issues

Overview

Fix HTTP HEAD request handling errors where servers return incorrect headers, response bodies, or different Content-Length than the corresponding GET request.

Key Details

• HEAD requests must return the same headers as GET but without the response body
• Content-Length in HEAD response must match what GET would return
• HEAD is used by caches, crawlers, and link checkers to validate resources without downloading
• Some frameworks do not automatically handle HEAD requests, returning 405 Method Not Allowed
• HEAD responses must not include a message body, even if Content-Length is set

Common Causes

• Web framework not automatically mapping HEAD requests to GET handlers
• Server returning a response body with HEAD requests (violates HTTP spec)
• Content-Length mismatch between HEAD and GET responses due to dynamic content
• Middleware or compression changing headers between HEAD and GET responses

Steps

1. 1Verify your framework handles HEAD automatically: most frameworks (Express, Django, Rails) route HEAD to GET handlers and strip the body
2. 2Test HEAD vs GET: 'curl -I https://your-server.com/resource' should return the same headers as 'curl -v https://your-server.com/resource'
3. 3If Content-Length differs, ensure compression headers are consistent between HEAD and GET
4. 4Add explicit HEAD route handlers if your framework does not auto-map them
5. 5Monitor for HEAD request failures using web server access logs — search for HEAD requests with non-200 status codes

Tags

More in 2xx Success

Frequently Asked Questions