HTTP/2: What are the most important advantages for WordPress sites?

Gijs Hovens, December 8, 2017

Http/2 supportedThe HTTP protocol is the backbone of the web. But thanks to ever-growing use of the Internet and the increasingly stringent requirements demanded of our digital infrastructure, the protocol is slowly starting to show its age and shortcomings. But there is an alternative; Savvii has introduced the HTTP/2 protocol.

HTTP/2 is a new technology that makes loading a website via a secure connection considerably quicker. What’s more: An SSL secured website using HTTP/2 is quicker (and more secure) than a website without SSL. What exactly is it and what are the most important advantages of this new protocol for your WordPress website?

The limitations of the HTTP protocol

The Internet community has been using the widely known HTTP (HyperText Transfer Protocol 1.1) since 1991, a protocol that was updated to HTTP 1.1. in 1999. HTTP enables browsers to communicate with servers. But the digital world is evolving rapidly. The result is that the limitations of HTTP 1.1, which has been superseded by time and technology, are becoming more and more apparent, particularly when it comes to processing increasingly congested Internet traffic. The number of web pages requested has increased exponentially in recent years. The number of assets (images, CSS, fonts, videos, scripts, etc.) per page has also increased. The effects are obvious: longer loading times and more pages that are inaccessible.

The limitations of HTTP 1.1 can be circumnavigated to some extent by using technologies such as minifying, lazy loading, caching and domain sharding, but those solutions are not completely satisfactory.

The advent of HTTP/2 support

It is therefore unsurprising that website developers are yearning for a better solution to the abovementioned problems. Enter HTTP/2 support. This innovation, launched in 2015 and recently introduced by Savvii, is based primarily on the SPDY protocol, an ambitious project by Google that facilitates quicker loading of websites. HTTP/2 meanwhile also has a recognised IETF standard and is thus supported by most modern browsers. Note: to be able to use HTTP/2, your WordPress website must have an SSL certificate (secure connection).  Savvii has arranged that for you with a free SSL certificate from Let’s Encrypt.

What are the main advantages of HTTP/2?

HTTP/2 support for WordPress websites offers a number of important advantages compared to HTTP. The new protocol’s trump card is speed. Although it is possible to start multiple requests in HTTP 1.1 at the same time, a common problem is that a new request can only be processed once a previous request has been completed. This phenomenon, called head-of-line-blocking, is similar to a queue at the checkout in a physical shop caused by a customer with that one annoying query. HTTP/2 solves this problem with multiplexing. All requests are amalgamated and sent to the browser in a single connection. You could say that all customers are served at the same time.

Http/2 Loading timesAdditional benefits of HTTP/2 for WordPress

Apart from multiplexing, HTTP/2 support offers even more advantages for your WordPress site. The most important benefits at a glance:

  • Prioritisation: loading of website files must take place in a specific order. For example, is a CSS file only loaded at the end? Then this can result in a website without a design. On the other hand, loading JavaScript too late means certain functions on the WordPress website will not work. In HTTP 1.1, you can specify the order with head-of-line-blocking. That is no longer necessary with HTTP/2: all requests are routed through a single connection and the browser itself determines the priority for each file type.
  • HTTP/2 compresses all HTTP headers and sends them via a single connection. The binary headers in HTTP/2 (they are still textual in HTTP 1.1) are less sensitive to errors and ensure a quicker loading time.
  • In HTTP 1.1, files are only loaded when the browser retrieves them from the web server. In HTTP/2, files can be proactively loaded via ‘server push’. That way, a new web page for which other files are necessary can be presented immediately without having to make a new connection.
  • Thanks to compression, HTTP/2 headers are considerably smaller and therefore also quicker (they save on bandwidth).
  • The new protocol is more secure than its predecessor.

Website building and HTTP/2 support

It is clear that HTTP/2 offers many advantages over the older HTTP protocols. But how do you benefit optimally from the advantages offered by HTTP/2 when building a WordPress website? The beauty of HTTP/2 is that it is backwards-compatible with 1.1. In other words: an upgrade will not harm your website in any case. In addition, it is important to convert the website into HTTPS insofar as that is not yet the case. As it happens, HTTP/2 is only supported if your website has SSL security. In addition, there are a few aspects of the building process that are important for HTTP/2 to truly come into its own:

  • First, check whether your hosting already supports HTTP/2. You can do this via the test on Note: ALPN must also be supported in order to benefit from all the advantages offered by HTTP/2.
  • In HTTP 1.1, it is easier to retrieve a large image file than it is to make various requests for different small image files. Hence the popularity of so-called sprites (which amalgamate numerous images into a larger one) to circumnavigate queues on the server. This is no longer an issue with HTTP/2 and in many cases, it is better to use multiple smaller image files when building a WordPress website. That way, visitors only get what they need to view a certain page and you no longer need to download any large files to view a photo or specific section of the website, for example.
  • With HTTP/2, domain sharding (spreading the elements of a website, such as images and scripts, across multiple domains) is superfluous because thanks to the new system, you can process and receive a virtually unlimited number of requests simultaneously.

HTTP/2 at Savvii

HTTP/2 thus offers owners of WordPress websites many advantages over HTTP 1.1. A site with HTTP/2 support is quicker, more efficient, more secure and far better suited to the demands that modern Internet traffic places on servers. 95% of our sites now run on HTTP/2 and the other 5% will follow in January. In any case, we are rolling out all new sites in HTTP/2.

Curious about other ways of making your sites faster? Read our whitepaper on speed or check our How to make your WordPress website faster: the ultimate checklist to find out the correct way to measure and improve the speed of your website.

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