Sentinel: Your Web-Performance Watchman

Web Performance Back to Front

Taking you on a journey from the back-end all the way to the front, Web Performance Back to Front is my first workshop designed specifically to be delivered remotely. It looks at all of the ways to audit, assess, and fix performance issues starting way back on the server, across the network, and right into the browser.


I can’t thank you enough—it’s been brilliant and we’ve learnt a lot (to say the least)!

You never quite realise how little you know about a subject until you meet a real expert, so we’re really grateful for your time.

Tom Houdmont, Solution Architect, Box UK

Web Performance Back to Front is designed to take a look at all aspects of the site-speed spectrum. Starting with a look at everything that is happening on the server and CDN, everything across the network, all that takes place in the browser, and each bit in between—we’ll cover it all.

In order to keep the workshop engaging, relevant, and practical, it takes the form of a real-life performance audit of your own sites and projects—a true insight into my own process employed on some of the largest sites in the world. We’ll work together over a series of sessions to audit, inspect, and uncover performance bottlenecks on the projects that matter to you.

The workshop is divided into five key topics that seamlessly follow on from the last on our journey from the back-end to the front.

  1. Getting to Know a Website: How to quickly determine the topography of a site, how to get our tooling set up to be the most forensic possible, and using other tools to complete the picture.
  2. Server, CDN, and Network: Analysing and troubleshooting back-end issues from the browser, determining whether our CDN is working as expected, and looking at our sensitivity to network performance.
  3. The Browser and Assets: How does the browser handle resources and requests, and how can we set the browser up to best take advantage of that?
  4. Third Parties: Peeling back the layers and stepping confidently into the minefield that is third parties. I promise you, it’s not as bad as you think.
  5. Performance Culture: Setting performance budgets, monitoring, and keeping on top of things.

Remote by Default

With the move to remote work rapidly spurred on by 2020’s Coronavirus pandemic, I went right back to the drawing board to design a workshop format specifically optimised for remote delivery. Short, focused, and intensive sessions with a clear topic, all recorded for you to keep forever.

However, day-long video calls are tiring. It’s difficult to stay engaged and it’s easy to lose focus—this is the last thing you want when you’re trying to learn. To combat this, the five sessions are delivered over five consecutive days: 5× two-hour sessions run across the course of a week.

Each day, we meet to take on a new theme, each compartmentalised into its own micro-workshop with very clear confines and remits. This means that rather than trying to juggle a whole week’s worth of learning, we can hit the reset button each morning and look at something new. Because all of the sessions are recorded, you can dip back in whenever you like. Need to recap third parties? Skip to session four! Want to relocate a DevTools setting? Check your notes from the first session!

By the end of the week, we’ll have covered the entire web performance gamut in five individual sessions; we’ll have actionable insights and action points for our own projects and work; we’ll have a whole host of new resources and tools; and we’ll have it all recorded to keep forever!

Sound good?

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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.

Suffering? Fix It Fast!


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  • Talk & Workshop

    WebExpo: Prague (Czech Republic), May 2024


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.