No need to merge CSS or JS files if you are using HTTP/2

With the increasing adoption of HTTP/2, the performance of web applications has been greatly improved. One of the most significant improvements in HTTP/2 is the way it handles resource files such as CSS, JavaScript, and images. In traditional HTTP/1.1, merging these files into a single file was a common optimization technique to reduce the number of requests and improve performance. However, with HTTP/2, this technique is no longer necessary. In fact, merging resource files on HTTP/2 can actually hurt performance.

Here are some reasons why you don’t need to merge resource files on HTTP/2:

  1. Multiplexing: One of the key features of HTTP/2 is multiplexing, which allows multiple requests to be sent and received on a single connection simultaneously. This means that the browser can request multiple resource files at once without waiting for a response. As a result, the number of requests is no longer a bottleneck for performance.
  2. Stream prioritization: HTTP/2 also introduces stream prioritization, which allows the browser to prioritize which resources should be loaded first. This means that the browser can load critical resources such as CSS and JavaScript before loading images, which can improve the perceived performance of the page.
  3. Server push: Another feature of HTTP/2 is server push, which allows the server to send resources to the browser before the browser requests them. This can further reduce the number of requests and improve performance. However, server push should be used with caution as it can also hurt performance if not implemented correctly.
  4. Caching: HTTP/2 also improves caching by allowing the browser to cache individual resources instead of the entire file. This means that if a single resource changes, the browser can still use the cached version of the other resources, which can improve performance and reduce the amount of data transferred.

Merging resource files on HTTP/2 is no longer necessary and can actually hurt page speed. Instead, focus on optimizing each resource file individually and take advantage of the new features of HTTP/2 such as multiplexing, stream prioritization, and server push. By doing so, you can improve the performance of your web application and provide a better user experience for your users.