4 Apr 2017 • 7 minute read Web performance is something I care deeply about both as a developer whose work affects millions of people around the world, and as a user who often accesses the web on slow & unreliable connections. I have regularly and loudly complained that the BBC News website is unnecessarily slow, so when I was given the opportunity to help rebuild one of the most visited pages of BBC News—the front page—I jumped at the chance.
That was April 2016. Now, a whole year later, we’re ready to begin a phased rollout of the new front page. Starting with a small percentage of users in the UK, we will gradually move everybody to the new front page over the course of several weeks. (Update: as of June 2017, the new front page is rolled out to all users).
Quick facts about the new front page
- It is lighter and faster than the old one:
- First meaningful paint happens up to 50% sooner on mobile devices.
- Page enhancements like lazy-loaded images load 150% faster on mobile, and 70% faster on desktop.
- The total bytes downloaded is 50% less on mobile and 75% less on desktop.
- CPU busy time has been reduced by 30% on mobile and by 50% on desktop.
- Performance monitoring has been automated with SpeedCurve from the beginning of the project.
(Read more) 13 Feb 2017 • 5 minute read This post is about the Web Application Framework in use by some teams at the BBC. It is not strictly a framework in that it specifies the contracts between components, rather than providing concrete implementations of the components. For this reason, I prefer to think of it as the Web Application Specification.
At the beginning of 2015, a group of developers and technical architects from around the BBC got together with the goal of designing a system for sharing web page components between teams. This came from an acceptance that most of the BBC’s public-facing web products have a similar look & feel, and a desire to improve efficiency through sharing rather than building similar things over and over again.
(Read more) 26 Dec 2016 • 8 minute read The BBC is a pretty large organisation. Today it employs around 20,000 people (actually around 35,000 when you include part-time and fixed-term contract employees) across a huge number of divisions. The BBC Careers website typically has over 100 vacancies posted on any given day. Before I joined the BBC, I found the sheer scale of it a bit intimidating. Usually I can get an idea of what it’s like to work for a company by reading their job advertisements and their engineering blogs, but with the BBC I was almost completely clueless. In this post I hope to shed some light on what it’s like to work as a developer or tester for BBC News.
Just a small disclaimer first: from an engineering perspective, the BBC is not like most other companies — it’s more like dozens of smaller companies, each with their own engineering department, working towards a common goal. News, Sport, Programmes, iPlayer, Radio… As digital products, these are all built mostly independently of each other. I work for BBC News, so a lot of what I’ve written may not apply outside of BBC News.
(Read more) 22 Jul 2016 • 16 minute read TL;DR: Over the last 4 years, the BBC News core experience has been transformed from a speedy 21KB page into a slow & bloated 685KB monster. This was in part due to a lack of performance monitoring and 4 years of feature creep, but also due to a lack of performance-oriented culture throughout the business.
I created a lightweight prototype of the BBC News core experience which demonstrates that focusing on the content first and foremost can result in an extremely fast page. I want the BBC and other websites to rethink what the core experience means, and experiment with giving users the power to define their own experience.
In the beginning of 2012 the BBC Responsive News team wrote about how they provide a “core experience” for users by default, and then progressively enhance the page if the browser cuts the mustard. At the time, this was cutting edge. They were able to build pages that worked on practically any browser without compromising the experience for users on modern browsers. To quote directly from the Responsive News blog:
(Read more) 20 May 2016 • 5 minute read Back in December 2015 I spoke at LDNWebPerf alongside Peter Chamberlin about how web performance is not a technical problem (slides with speaker notes). One of the things I talked about was how we used multivariate testing (MVT) at BBC News to prioritise performance optimisations. The gist of it was that our stakeholders had already bought into the idea that performance has a strong correlation to business metrics, and they wanted to dedicate some development time to improving performance. The catch was that they didn’t want to spent too much time on it.
Our predicament, then, was that we needed to know which optimisations had the biggest impact on performance without actually spending the time to make the optimisations. For example, we had a hunch that inlining the critical rendering path CSS would improve our start render time, but with over 1MB of CSS and a complicated application architecture, implementing this was much easier said than done.
This is where the idea to A/B test performance came from: we could easily make the performance optimisations by hand on a single page, and then benchmark each of the optimisations to find out which had the biggest impact.
(Read more) 