https://en.ryte.com/magazine/improve-webpage-load-speed-http-2-beginners-guide

HTTP/2 can significantly improve your website’s page speed because it allows browsers to simultaneously process multiple requests over the same connection. In this article, learn how you can easily improve your site’s load speed with HTTP/2.

..When HTTP was first created, this wasn’t such a big deal. Back then, webpages tended to look like this:

netscape improve webpage load speed improve load speed with HTTP/2 HTTP/2 beginner's guide to improving webpage load speed with HTTP/2

Figure 1: Websites in the age of HTTP/1

That entire webpage consists of two files: the HTML webpage and a single image banner. With dial-up internet speeds being the fastest thing available, website creators couldn’t get very fancy. But with only two files, being limited to downloading one file at a time wasn’t a problem.

Today’s webpages are far more complex. For example:

  • The homepage of amazon.com requires 315 separate requests/files.
  • The homepage of cnn.com triggers 521 separate requests for files.
  • The homepage of ebay.com makes 256 separate requests.

As you can see, it would be very inefficient to download these files one at a time, or even to download 6 at a time. That’s the problem that HTTP/2 fixes.

HTTP/2 allows browsers to simultaneously download multiple files over the same connection. This makes it a lot faster for the user to download all the files needed for a given webpage.

If you’d like a simple (but detailed) explanation of how HTTP/2 works, I recommend An introduction to HTTP/2 for SEOs by Tom Anthony. It’s even got great little illustrations using trucks that help make a intangible concept super-easy to conceptualize and understand: