Sentinel: Your Web-Performance Watchman

Performance Audits

You could be leaving hundreds of thousands of dollars of revenue on the table every year due to a poorly- or un-optimised website. Slow websites are one of online consumers’ biggest frustrations, and a fast way to miss out on sales.

Whether you want to boost revenues, improve conversion rates, reduce churn, or improve retention and engagement, a well-optimised site is a key way to get there.

Need Answers Now?

Schedule a tactical audit to find and fix site-speed issues in your project immediately.

How It Works

All it takes is five straightforward steps to turn your site around:

Harry’s performance audit gave comprehensive, forensic insight across the full delivery pipeline. Clearly highlighted priorities brought rapid benefits and a plan for continued improvement. Genius.

Peter Gibb, ICAEW
  1. Survey: To begin, I need to know a lot about your organisation, the problems you feel you face, and what we need to concentrate on. I’ll send a series of very focused questions that will help me to understand the business’ needs immediately.
  2. Audit: Remotely, I roll up my sleeves and dig in! With an encyclopaedic knowledge of all things web-performance, nothing will evade me. From infrastructure and the network, to assets and payloads; from CSS and fonts, to runtime and rendering (and everything in between), we have a lot to pay attention to. I’ll spend at least five days looking through everything I can get my hands on.
  3. Report: Once I’ve uncovered everything, I’ll put together a full report outlining all of the issues and problems that exist, as well as preemptive optimisations we could make in order to be even faster. The report will contain actionable and prioritised tasks that you and your engineers can begin to implement in a sensible and considered order.
  4. Handover: Once you and your team have had chance to read and digest the report, you’ll likely have some questions or comments. We’ll hold a formal handover session to ensure that you fully understand the entirety of the audit document and know what you need to do next.
  5. Reconvene: One to three months later—depending on what would be most helpful for you—I’ll drop back in and conduct a brief re-audit against the backlog that I left you with. This phase ensures you’re accountable, as well as shows me where any regressions may have happened or what you may have struggled to overcome.
A full Trello board forms the basis of your Performance Sprint.

Existing Issues and Opportunistic Optimisations

Harry’s focused, practical approach allowed us to implement significant changes which improved our user experience and overall performance dramatically. I recommend him wholeheartedly.

Rich Fogarty, Concrete Playground

As well as uncovering existing issues that are impacting site performance, I’ll also be sure to make recommendations where opportunistic optimisations are concerned: are there any new web platform features we can utilise? Different approaches we could be taking? Bleeding edge features that we can begin to introduce? Instead of just making your site better, let’s make it a class-leader.


Once the audit is complete, you receive:

  • Executive Summary: A high-level, non-technical Keynote highlighting the biggest findings and their implications, as well as immediate- and short-term strategic advice for fixing the issues in question. This document is designed to orientate and align everyone with a shared understanding of the task at hand.
  • Performance Backlog: A Trello board that I populate as I review the site will be made available to your team. Cards have clear checklists covering everything from common pitfalls to long-term optimisations. Key tasks are created and loosely prioritised in order for your team to hit the ground running.
  • Half-Day Handover: Scheduled for some time after delivery of the report, we’ll set aside a half-day for a call in which your engineers can ask questions about my findings, I can explain anything that requires it, we can look to discuss longer-term strategies, and generally close up the project with a formal handover session.
  • Check-In: Rather than simply leaving you to get on with things unassisted, I will check back in within one to three months to see what progress has been made—and maintained!—as well as to see what outstanding issues or unresolved problems there might be.

Arrange an Audit

Fix It Fast!

Sometimes, a week-long audit is a little more than you need. Perhaps you only have a very specific issue you’d like to tackle; maybe you’re not sure how much input you need at all? For you, we have the Fix It Fast option: a quick-fire, tactical, and straight to the point screencast covering the most immediate problems you face.

Video is the ideal format for tactical problem solving.

You tell me the issue, I run some tests, and then record myself solving it. At the end, you’re left with a screencast showing exactly how I went about troubleshooting the issue, as well as its solution.

Fix It Fast is a very pragmatic response to the need for short, targeted advice that doesn’t require a full audit engagement. It can also be used to triage the extent of performance issues with your site.

Fix It Fast!

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!


  • inuitcss
  • ITCSS – coming soon…
  • CSS Guidelines

Next Appearance

  • 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.