Web Performance Optimisation, Consultancy, and Engineering

Trusted by:

Harry gave the team a strong footing for identifying performance issues on iPlayer. With his knowledge, we were able to roll out quick fixes to our audiences without the need for big rewrites, all within just two days.
Matthew Burrows, BBC iPlayer
Harry helped our team level up their scalable CSS architecture skills, and to say that he had a large impact on our work is an understatement. We can’t recommend him enough.
Addy Osmani, Google
Harry’s workshop was excellent; we left with tons of new ideas and techniques to improve both the CSS architecture and overall performance of Behance and Adobe Portfolio.
Jackie Balzer, Adobe
There’s a short list of people I whole-heartedly recommend for detailed performance work; Harry is right up there at the top.
Tim Kadlec
The CSS architecture I learned from Harry on the NHS project has changed the way I work. Bravo!
Josh Nesbitt

Web Performance and Site-Speed Insights

There are 240 articles on this blog. Find them all on the blog page.

4 January, 2017
Choosing the Correct Average
12 December, 2016
CSS Shorthand Syntax Considered an Anti-Pattern
30 November, 2016
CSS Wizardry Newsletter
28 November, 2016
Nesting Your BEM?
23 October, 2016
Improving Perceived Performance with Multiple Background Images
19 October, 2016
Continue Normalising Your CSS
15 October, 2016
Pure CSS Content Filter
10 October, 2016
Pragmatic, Practical, and Progressive Theming with Custom Properties
30 August, 2016
Refactoring CSS: The Three I’s
20 June, 2016
Speaker’s Checklist: Before and After Your Talk

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.

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ITCSS – coming soon…

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Web Day Out: Brighton (England), March 2026

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I help teams achieve class-leading web performance, providing consultancy, guidance, and hands-on expertise.

I specialise in tackling complex, large-scale projects where speed, scalability, and reliability are critical to success.

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