stale-while-revalidate helps developers balance between immediacy —loading cached content right away— and freshness —ensuring updates to the cached content are used in the future.

Have you ever been reading an article online when something suddenly changes on the page? Without warning, the text moves, and you've lost your place.

Total Blocking Time is a companion metric to Time to Interactive. For each task, it considers all time except for the first 50ms to be "blocking time". Total Blocking Time is, then, the sum of all the blocking time that fall between FCP and TTI.

If you're using a web font, you're bound to see a flash of unstyled text (or FOUC), between the initial render of your websafe font and the webfont that you've chosen. This usually results in a jarring shift in layout, due to sizing discrepancies between the two fonts. To minimize this discrepancy, you can try to match the fallback font and the intended webfont’s x-heights and widths [1]. This tool helps you do exactly that.

Accessibility is a holistic practice, essential to some but useful to all. It is a practice that touches on many aspects of good web design and development, especially performance. This talk will highlight opportunities and techniques to improve your website or web app’s performance by embracing an accessible, inclusive mindset.