In the quest for optimizing pages for performance, WordPress has had to resort to educated guesses about what to prioritize loading in order to display the page as fast as possible. Because WordPress is limited in how well it understands the layout of the page being served, it’s only about 50% effective at prioritizing the loading of the most important image (the Largest Contentful Paint element).

What if WordPress isn’t limited by its existing server-side heuristics but could instead be informed by client-side detection from actual visitors to optimize pages?

This is what the Optimization Detective project from the WordPress Core Performance team is all about. Optimization Detective improves WordPress’s page loading performance by utilizing real user metrics (RUM) to overcome the limitations of server-side heuristics.

This talk will dive into all aspects of Optimization Detective including:

• Gathering metrics from users anonymously via web-vitals.js.
• Leveraging the new HTML Tag Processor in WordPress core.
• Exploring the optimizations which are unlocked with real user metrics (RUM) beyond just prioritizing the LCP image.