HTTP 304 Not Modified

The resource has not been modified since the last request. The client can use its cached version.

What 304 means

HTTP 304 Not Modified tells the client that the cached version of the resource is still valid. The server doesn't send the response body, saving bandwidth. This is triggered by If-Modified-Since or If-None-Match conditional headers.

Common causes

• Browser has a valid cached copy
• ETags match between client and server
• Resource hasn't changed since last visit

How to fix it

• This is correct and desirable — it means caching is working
• If you need to force a refresh, update the ETag or Last-Modified header

SEO impact

Positive for SEO. Proper caching (leading to 304s) improves page speed, which is a ranking factor.

Monitoring tip

LemWatch accounts for 304 responses in performance monitoring. A healthy site should return 304s for unchanged static assets.