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Optimizing Web Vitals, case studies from GOV.UK and ManoMano & lessons learned from the fastest sites

Apr 1, 2022


Hi there,

As we approach the two-year anniversary since Google announced Core Web Vitals, it's become clear that Vitals are here to stay for a while. As they continue to evolve, there's a satisfying body of research and best practices that's evolving as well.

In this month's newsletter, you'll see references to Vitals throughout – particularly to Largest Contentful Paint, which seems to be the metric most of us can agree merits tracking. (It helps that LCP is also the simplest metric – relatively speaking – to optimize.)

While metrics are great – and certainly something we spend a LOT of time talking about here at SpeedCurve – they're just one tool in your performance toolkit. To wield them well, you need to have a strong performance culture that spans teams throughout your organization. That's why I've also included some inspiring case studies, as well as a performance guide geared toward Product Managers (or anyone else who needs a broad, high-level understanding of performance).

As always, I'd love to hear back from you. Please feel free to reply to this email with your feedback and suggestions about what types of resources you'd like to see in future newsletters. I'm not a bot, so I will definitely get back to you. :)

Until next time, I hope you stay safe, happy, and well.



Lessons learned from leading websites

Every month, I dive into the Industry Page Speed Benchmarks dashboard to look at performance metrics for top sites in a number of industries, including retail, travel, and media. The purpose isn't to focus on ranking, but rather to look at what makes the fastest sites fast (and the slowest sites slow).

One of the biggest takeaways from my most recent investigation: There can be a huge gap between Start Render and Largest Contentful Paint – especially on mobile. If you're not tracking LCP, you should be.

Optimizing Largest Contentful Paint

As Harry Roberts points out in this post, Largest Contentful Paint (LCP) is the easiest Core Web Vital to improve. It's also the most consistent across both synthetic and real user monitoring. In his post, Harry goes deep and shares a wealth of helpful tricks and optimizations, as well as some pitfalls and bugs.

Optimizing Core Web Vitals on SPAs

If you care about performance, then there's a good chance you care about Google's Core Web Vitals. And if you care about performance and have a single-page app, then you probably know that measuring Web Vitals for SPAs presents some unique challenges. In this detailed post, Simon Hearne reviews the most important optimizations you should consider making for your SPAs.

Removing jQuery and optimizing JavaScript at GOV.UK

Matt Hobbs shares a GOV.UK performance study in this epic Twitter thread. This thread contains more good stuff than I can include here, but a few highlights:

  • Key metrics like front-end time, First CPU Idle, and JS Long Tasks all saw improvement
  • Users at the 95th percentile (read: those who typically suffer the worst performance) experienced significant improvements
  • Users on mobile devices saw improvement as well

Web performance for Product Managers

As a Product Manager, you may find yourself needing to ramp up quickly on web performance. If you're new to performance (and even if you're not a PM), this guide covers concepts and guidelines to get you up to speed, including:

  • What makes a page slow?
  • How is performance measured?
  • What do the different metrics mean?
  • How to use percentiles
  • How to communicate with teams

ManoMano's web performance journey

All the metrics and monitoring tools in the world can't help you if your company doesn't have a strong web performance culture. That's what the team at ManoMano discovered.

ManoMano is an online marketplace that attracts 50 million visitors a month in six counties. In a series of articles, starting with this one, Stephane Biancotto presents "how we have brought performance back to the heart of the company strategies, moving from a blind vision to a less and less blurry one over the months."

Mark your calendar!

Photo of SmashingConf audience throwing balloons in the air

We're very excited to be supporters of some of our favourite in-person events returning this year. I'm planning to get to at least a couple of these events. Maybe I'll see you there!

DYK: We have a video series to help you investigate performance issues? We do!

Check out the SpeedCurve video playlist for a series of short video explainers that cover things like:

Is there a video you'd like to see that's not there? Let us know by replying to this email!