Safari’s getting Core Web Vitals in 2025. Are you ready?
When Google announced Core Web Vitals were coming to Chrome in 2020, the web performance industry was a frenzy! Everyone wanted to get their sites in shape, and it was a great time for web performance.
Five years on, Core Web Vitals have worked! The web as an ecosystem has gotten steadily faster across the board:
Or has it?
It’s important to view Core Web Vitals through two distinct lenses:
These two points yield two corresponding problems…
This means that we’ve had zero visibility of the Core Web Vitals metrics on iOS or any flavour of Safari at all. If you’re based in North America or northwestern Europe, that may mean the majority of your audience is completely unaccounted for.
However, things are about to change.
Apple announced that Largest Contentful Paint and Interaction to Next Paint would be coming to Safari as part of the Interop 2025 project! This means that we can begin tracking and instrumenting two of the three Core Web Vitals before the end of the year!
If you’ve been focusing on Core Web Vitals for your Chrome visitors already, you’re well poised. But are you prepared for what it might mean for the business? Are your developers prepared for the different rendering engine? Do you know how to track site-speed in Safari if the data doesn’t go into CrUX?
To help prepare clients—both new and old—I’ve designed a one-day workshop covering, but not limited to:
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
The goal is to leave the team aware of the upcoming changes, arm them with tools and knowledge to optimise for the different engines, and ensure that your Safari users aren’t being overlooked.
I much, much prefer in person workshops—it means we can hang out and probably head for drinks after! But as it’s only a single day, running the workshop remotely works pretty naturally. Remote workshops will be recorded for you to keep.
Ready? Let’s get it booked in!
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.
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.