Web Performance Optimisation, Consultancy, and Engineering

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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.

2 October, 2023
How to Clear Cache and Cookies on a Customer’s Device
28 September, 2023
The Ultimate Low-Quality Image Placeholder Technique
24 July, 2023
Core Web Vitals for Search Engine Optimisation: What Do We Need to Know?
11 July, 2023
The HTTP/1-liness of HTTP/2
1 July, 2023
In Defence of DOMContentLoaded
7 June, 2023
Site-Speed Topography Remapped
10 January, 2023
Why Not document.write()?
12 October, 2022
Speeding Up Async Snippets
6 September, 2022
Critical CSS? Not So Fast!
24 August, 2022
Measure What You Impact, Not What You Influence

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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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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