HTTP/2 is a significant overhaul to HTTP, the protocol for hypertext-based communication that handles the bulk of data transfer on the World Wide Web. This update has been a decade and half in the making, and soon servers and clients alike will all be able to use it.
What are the advantages of HTTP/2.
HTTP/2 makes significant improvements to the existing HTTP protocol, especially with page load times, such as:
- Connections are now parallel and fully multiplexed, so multiple data assets can be transferred faster and more efficiently over the same TCP request.
- The protocol is binary, so the commands in the form of 0s and 1s that are transferred over the wire are more efficient, unlike the human-readable commands used up to HTTP 1.1.
- The new ‘server push’ concept allows the server to send resources in anticipation of the needs of the client, while still allowing the client to reject the pushed data.
- Compressed HTTP headers that avoid the need to re-send headers.
How compatible is HTTP/2?
HTTP/2 strives to make HTTP better, but to get there, it has to work well with the existing infrastructure of the internet:
- It supports all browsers, so if your site uses HTTP/2, there’s no scenario where it prevents a visitor from accessing your site. Newer browsers that are compatible with HTTP/2 will work of course, but those aren’t compatible will switch to HTTP 1.1 without so much as a hiccup. Of course, the new protocol doesn’t affect how the site looks, just how well it performs or how quickly it loads.
- It will directly work with your existing TLS certificate, and you don’t need to tweak anything. However, do remember that only secured domains work with HTTP/2 right now, though this should change as more and more browsers add HTTP/2 cleartext support.
- You can use HTTP/2 with major existing services like Cloudflare that support all the way up to even HTTP/3
- Most hosting services enable HTTP/2 by default. The HTTP/2 web server from Zalvis, for instance, works from the get go.
Testing
We can test that the enabled HTTP/2 on your website by using online tools such as KeyCDN’s HTTP/2 Test (https://tools.keycdn.com/http2-test) and ensure that the protocol is indeed working for you.