Site-Speed Optimisation – Web Performance and Site Speed Consultant

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

Articles

There are 248 articles on this blog. Find them all on the blog page.

21 June, 2015
Travelling Like You Want to, When You Have To
13 June, 2015
Contextual Styling: UI Components, Nesting, and Implementation Detail
11 June, 2015
Subtleties with Self-Chained Classes
26 April, 2015
Cyclomatic Complexity: Logic in CSS
11 March, 2015
Immutable CSS
8 March, 2015
Can CSS Be Too Modular?
6 March, 2015
More Transparent UI Code with Namespaces
20 November, 2014
When to use @extend; when to use a mixin
29 October, 2014
The Specificity Graph
24 October, 2014
CSS Wizardry Ltd.: Year 1 in review

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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Projects

ITCSS – coming soon…

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Talk
Devoxx Greece: Athens (Greece), April 2025

Learn:

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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