304 Not Modified

A 304 Not Modified status code is an HTTP response status code indicating that the resource has not been modified since the last request. This status code is sent by the server to the client (usually a web browser) when it performs a conditional GET request, and the server’s cached version of the resource matches the one requested.

Importance in SEO

The 304 Not Modified status code is important for SEO because it helps to save bandwidth and improve page load times by preventing the transfer of unnecessary content. When a server responds with a 304, it means that the client’s cache can be used, which can lead to faster page loads and a better user experience.

This, in turn, can positively impact SEO by signaling to search engines that the website is optimized for performance.


For instance, if a user revisits a webpage that they have previously viewed, and the webpage has not been updated since their last visit, the server can respond with a 304 Not Modified status code, and the browser will use its cached version of the page instead of downloading the page again from the server.

  • Implement conditional GET requests: Use the If-Modified-Since or ETag headers to check if the resource has been modified before downloading it.
  • Optimize caching headers: Ensure that your server sends appropriate caching headers to control how long a resource should be cached by the client.
  • Monitor caching effectiveness: Use tools to analyze your website’s caching performance and make adjustments as needed.


  • Avoid sending 304 responses when the resource has changed: This can lead to users viewing outdated content.
  • Avoid sending 304 responses for resources that should not be cached: Some resources, like user-specific data, should not be cached and should always return a 200 OK status code.
  • Avoid relying solely on client-side caching: Server-side caching can also be beneficial for performance, especially for dynamic content.

By properly using the 304 Not Modified status code, website owners can enhance the user experience and potentially improve their search engine rankings, as faster-loading websites are often favored by search engines.