Respond 16: Performance – HTTP2 in a 1.5 World – Peter Wilson

Peter Wilson’s subject at Respond 16 was performance, which sits alongside security as a major factor designers and developers have to take into account on today’s web.

You may have the most beautiful and useful website in the world, but if it takes too long to load, site visitors are unlikely to stick around to even see it. There are a few factors that make this so, and a few options for addressing it – not least the introduction of HTTP2.

Peter’s talk updates us on progress toward full implementation of HTTP2, including why it might not be as immediate a solution as hoped for. Here’s our Wrap magazine summary.

Performance: HTTP2 in a 1.5 World

Peter Wilson, WordPress Engineer, Human Made

Peter Wilson

Key points

The internet is slow. Pages load slowly and users abandon them.

HTTP2 is here to solve all our performance woes. Well, not quite, even on the 5% of websites that enable it, around 50% of traffic uses the older, slower protocol. It’s our job as web developers to account for both.

Discover some of the techniques available to developers during this transitional period, the new catches in HTTP2 and – importantly – how to keep your visitors from giving up before your site even loads.

“Amazon discovered it would cost them $1.6 billion in sales annually were their site to slow down for a mere second.”

Respond 16: Peter Wilson


From the truncation of the first message sent via a nascent Internet in 1969, performance issue have been with us.

Currently, average page weight accessed by desktops and laptops is at 2.3Mb, while mobile pages average 1.2Mb.

A typical web page takes up to 15.2 seconds to fully load, and that’s on a desktop with a fast, wired connection.

Poor performance costs money. Major web traders lose millions when their web pages load too slowly.

HTTP 1.1 requires many data round trips from server to browser and back again, in sequence. HTTP 2 processes multiple browser requests simultaneously, reducing load time.

We need to press for HTTP 2 being used on web servers.


Server push speeds up loading but can result in re-loading assets already present. It needs to be told to check the browser cache.

HTTP 2 has increasing but not universal browser support.

Use tools like WebPageTest to find out and address what’s really slowing down your page load.

Currently, 90% of web servers still run HTTP 1.

Even on servers running HTTP 2, 40% of site visitors still have to use HTTP 1 due to browser support.

Techniques that boost performance in HTTP 1 can have the opposite effect in HTTP 2.

Ultimately, we still need to consider and address our page weights, how and why we load page assets.

Respond 16: Peter Wilson



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