HTTP 304 Not Modified

What is HTTP 304 Not Modified?

The 304 (Not Modified) status code indicates that a conditional GET request has been received and would have resulted in a 200 response if the condition was not true. The response has no body — the client should use its cached copy. This is the foundation of HTTP caching, allowing browsers to validate cached resources without re-downloading them.

Common Use Cases

• Browser cache validation with ETag headers
• Cache validation with Last-Modified headers
• Reducing bandwidth for frequently accessed resources

// Laravel - ETag-based cache validation
return response()
    ->file($path)
    ->setEtag(md5_file($path))
    ->setLastModified(new \DateTime('@' . filemtime($path)));
// Laravel automatically handles 304 responses