Is This the Most Important Thing in UX?
Is unbeatable web performance the answer to the best possible user experience?
In short, yes. Web performance is included in our process to ensure users are able to have the best experience possible, no matter what device they are using or what their connection speed is like. Our products have visitors from all over the world and we want to give everyone an equal opportunity to access the information they need.
We focus on a worst-case scenario. We know not everyone can afford the latest iPhone or Galaxy S20, so we test our pages with an effective connection of 1600/768/200ms on a simulated mid-tier device. This device is currently a Moto G4 which will highlight any performance bottlenecks, especially with javascript execution, rendering, and animations.
Our journey for speed started back in 2017 with ‘Speed Week’. All the engineers got involved across all our products to improve First Meaningful Paint (FMP) with some well-known tried and tested techniques. Creating a separate stylesheet containing all the styles needed for the initial layout in the viewport and deferring all non-critical scripts saw an improvement of over 50% for FMP. Moving these styles from an external file to the head of the document placed after all scripts gave us an additional 100–200ms of savings over our test connection. This meant we were able to deliver the visible content to the user sooner.
Today, we focus not just on the metrics from the current Core Web Vitals (LCP, CLS, FID) but others like First Byte Times, Visually Complete, Fully Loaded Time, and Page Weight. This ensures that our visitors get a fast page experience across the whole page load. We use tools such as WebPageTest, Lighthouse, GTmetrix, and the CrUX dataset to measure and compare our performance. We’re also lucky to currently have a dedicated squad bringing together LAB data and RUM into one place to give us maximum visibility to get fast and stay fast across all our products.
It’s not just our Engineers that help us to achieve results. Our channels are open to all Chapters, (that’s iTech for departments,) with information sharing being a key practice for us. We do this via an internal blog, through guides and documentation, group messaging, and of course, TIM talks. They’re sort of like TED talks, but run in-house.
One recent collaboration across Chapters to achieve web performance results was with UX & Design where we reduced the number of custom fonts downloaded to the client by more than 50%. Another example with Conversion — where together we tested an approach to reduce the site-wide impact of third-party scripts.
To stay on top of your game, it is vital to be constantly experimenting with products. At iTech, we favour an all-hands-on-deck approach, which is why we can routinely celebrate our wins, and fails. As the web performance goal post continues to move, we are always doing our best to get ahead and stay ahead.
