Sentinel: Your Web-Performance Watchman

BSkyB: Senior UI Developer

Written by on CSS Wizardry.

Table of Contents
  1. Aluminium
  2. Mobile

For almost three years, I was employed by BSkyB (Sky) as Senior UI Developer. I worked primarily in their Betting & Gaming arm; a suite of highly trafficked and very highly profitable online products.

As you can imagine, over three years of employment, my responsibilities were incredibly varied: development work, design and design process rationalisation, internal workshops, performance engineering, and more.

One of my first tasks when I joined Sky was to rebuild the front-end of Sky Bet, for which I was the sole front-end developer. From there on in, I steered the majority of decisions regarding how we should go about building our UIs. This took the form of

  • building internal frameworks and UI Toolkits for other developers to implement;
  • providing a design–development bridge, and handling des–dev relations;
  • running internal workshops with design and engineering teams;
  • becoming product-agnostic, and moving from scrum to scrum to help out whichever teams needed me;
  • pairing and reviewing code written by other developers;
  • evangelising architectural and performance best practices within the company;
  • generally improving the techniques and approaches Sky took to writing UIs at scale.
Screenshot of the Sky Bet homepage. View full size/quality (672KB).


After Sky Bet was launched, and my time was getting increasingly stretched between products, I—with input from members of the design team—began work on Aluminium, a UI Toolkit built on top of inuitcss. Aluminium’s aim was to allow other developers (particularly non-front-end savvy Software Engineers) to build UIs out of a library of consistent, on-brand components. While Aluminium was being used by other engineers to build other products, my time was freed me up to work on one of the most exciting and ambitious projects I have ever been a part of: Mobile Sky Bet.


Sky Bet was hit by an unusually early uptake in mobile users; far earlier and more dramatically than a lot of other industries and sectors were reporting at the time. Having only just finished work on the classic, non-responsive ‘desktop’ build, it was decided that we respond very quickly and build a specific m-dot site as our mobile offering. Once again, I was the solo front-end developer on this project, and it was around this time we also employed a dedicated Performance Engineer, who I worked very closely with to ensure our UIs were just as speedy as his software and platform code.

Harry was always acutely aware of the performance implications of what we did and was always sure to improve the speed of the things we were working on. He’s great at rationalising and pushing back on design requirements that could adversely effect performance and working out better and faster ways of achieving the same result.

Dan Rathbone, Lead Performance Engineer, BSkyB

The results were fantastic, and Mobile Sky Bet was one of the best, most successful perf projects I’ve ever been a part of. You can actually watch a small dissection of that process in my talk, Normalising Designs for Better Quality CSS.

After my tenure at Sky, during which I’d worked on instilling a performance-led approach to design; better CSS architectures for their products, and a rationalised design process, I decided that I wanted to go it alone and do the same kinds of things for clients all over the world.

In total, I had a direct impact on all of Sky Betting & Gaming’s digital products, be that through direct development and engineering work, through frameworks and tools I’d written, to code reviews and workshops with other team members. Working at Sky was an incredible experience, and I’d recommend it to anyone.

Hi there, I’m Harry Roberts. I am an award-winning Consultant Web Performance Engineer, designer, developer, writer, and speaker from the UK. I write, Tweet, speak, and share code about measuring and improving site-speed. You should hire me.

You can now find me on Mastodon.

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I am available for hire to consult, advise, and develop with passionate product teams across the globe.

I specialise in large, product-based projects where performance, scalability, and maintainability are paramount.