The Non-Technical Guide To HTTP/2

TLDR: HTTP/2 makes websites “naturally” faster which makes for much better user experience. If you are building new site, definitely go for it. If your site is already up and running, check whether any of your existing speed optimisation is not going to stand in the way.

Did you know that absolute majority of websites you’ve used today technically still uses the same protocol, which was designed in (and for) the late nineties? Indeed, HTTP1.1 standard was officially released in January 1997. That’s 19 months before Google was founded, 10 years before the first iPhone was introduced. It was early days of ICQ and the websites looked like this:

And yeah, Altavista was the search engine of the day.

What is HTTP and what’s wrong with it?

HTTP stands for hypertext transfer protocol and is a set of standards used to transfer data over the web. These standards or rules define how is this data formatted and what actions should browsers and servers take in order to display website correctly.

Now, since HTTP 1.1 version of this protocol comes from the nineties, its possibilities are quite limited for the increasing demands of newer and more complicated websites:

HTTP 1.1 enables only one request per connection and browsers support maximum 6 connections per domain. Clever webmasters started “cheating” and were increasing possible number of connections per website through “domain sharding” = splitting resources into multiple domains.

Other downsides include client-only initiated requests, uncompressed request and response headers or only optional data compression.

Tip: If you are not sure what protocol is your company using, try installing these handy extensions, which will show you whether the page you are browsing is running on HTTP/1.1, HTTP/2 or SPDY protocol:

• For Chrome:
  https://chrome.google.com/webstore/detail/http2-and-spdy-indicator/mpbpobfflnpcgagjijhmgnchggcjblin?hl=en

So how does HTTP/2 save the day?

HTTP/2 is vastly based on Google’s SPDY (read as speedy) protocol and was officially launched early last year.

Long story short, HTTP/2 makes your site significantly faster. How much faster? That really depends on you and your website. In general, if your website uses HTML, CSS and JavaScript, contains images or other multimedia, the chance is you are going to benefit from it a lot.

Loading time is major factor for website abandonment. According to Kissmetrics, 40% of users will leave your website if it takes more than 3 seconds to load. The importance is even more crucial on mobile devices, which tend to be more prone to slower internet connection. Based on that, if an ecommerce makes £100.000 per day, 1 second page delay will potentially cost them £2.5 millions per year in lost sales.

HTTP/2 masters multitasking

The biggest improvement which HTTP/2 brings is that it’s multiplexed – this means that all the parts of your website, such as HTML, CSS, JavaScript etc., don’t block each other and can load in parallel. Thanks to this, only one connection is necessary, as there is no problem with “traffic jams” in data transfer.

HTTP/2 actually “listens” to you

Another new thing is Server Push. Imagine having a conversation with your friend, who only answers your questions. How fun and engaging would such conversation be? It’s similar with websites: in http1.1 it’s only the browser, which sends requests and server responds – by sending requested data. In HTTP/2, this browser-server conversation is more of a dialogue. Server Push enables server to send to your browser information before browser asks for it, making the whole process much more dynamic.

It’s compressed and binary

Other big difference is that HTTP/2 is binary – now that makes probably very little difference for us, SEO marketers, but this fact makes it more efficient, albeit harder to maintain.

Another improvement in efficiency of data transfer is the headers compression. Headers are an essential part of each HTTP request or response – they specify information about the client browser, requested page, server etc. As there are usually many requests going on, there is bound to be a lot of repetition. This is where HTTP/2’s HPACK compression comes in handy – reduces amount of data on the network.

How HTTP/2 helps your SEO

Admittedly, there are no direct bonus points for your ranking in Google simply from switching to HTTP/2. However the substantial increase of your loading speed, and through that improved user experience are an important signal for Google’s algorithm that your website means business. And as such Google might find it worthy of ranking boost.

If you haven’t switched to HTTPS already, consider this as another cue to do it – Most of the major browsers require websites to have secure connection in order to support the http/2. Now SSL used to make websites a little bit slower and expensive – as there was certificate needed per every connection. Since with HTTP/2 you can do with just one connection, this means significant savings in the loading speed as well as the costs.

Seriously, go secure – check out for example this initiative of Internet Security Research Group, which provides free and automated encryption certificates with pain-free implementation.

Summary

If you are still not sure whether HTTP/2 is the right answer for you, here is a little help:

1. Is the loading speed – or the happiness of you users important to you?
   If this is the case, you should definitely consider switching to HTTP/2.
2. Are you building a new site or working on a major redesign of the old one?
   This is the ideal situation since it means you do not have to fight any past HTTP/1.1 hacks. Go HTTP/2.
3. If your website has been around for some time: Do you have any http 1.1 optimisation techniques in place?
   This is a bit tricky. Some of the past “best practices” can be redundant or even obstructive if you decide to switch to HTTP/2.  If you still want to switch to HTTP/2, it will be essential to figure out which of these techniques are potential problems and you will have to get rid of them before taking any further steps.

Sources:

https://www.chromium.org/spdy/spdy-whitepaper

https://www.nginx.com/blog/7-tips-for-faster-http2-performance/

http://www.infoworld.com/article/2886381/internet/seven-no-bull-facts-about-the-new-http-2-protocol.html

https://http2.github.io/faq/#what-are-the-key-differences-to-http1x