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 237 articles on this blog. Find them all on the blog page.

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
15 August, 2014
CSS Guidelines 2.0.0
5 August, 2014
Advice to budding front-end developers
4 August, 2014
CSS Wizardry referral scheme
17 July, 2014
Hacks for dealing with specificity
23 June, 2014
Vim for People Who Think Things Like Vim Are Weird and Hard
21 May, 2014
Grouping related classes in your markup
2 May, 2014
My Trello workflow

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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Talk
ANWB Front-End Summit: The Hague (Netherlands), June 2025

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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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