Speeding up your website: Yahoo’s classic rules
The famous Yahoo performance rules in short, and which of them still matter today.
From the archive: in 2014 I shared “Best Practices for Speeding Up Your Web Site” by Yahoo’s Exceptional Performance team (Steve Souders and colleagues) on my old blog. This page is a short summary in my own words; the original belongs to its author.
Yahoo’s performance team found that most of the time a visitor waits is spent on the front end (downloading images, styles and scripts), not on the server. Their rules, grouped:
- Make fewer requests: combine files, use CSS for simple graphics, avoid unnecessary redirects and DNS lookups.
- Serve from close by: use a CDN for static files.
- Cache aggressively: long cache lifetimes for files that rarely change.
- Send less: compress text responses, minify CSS and JavaScript, optimise images.
- Order matters: styles at the top so the page renders early, scripts at the bottom (or deferred) so they don’t block it.
- Keep cookies off static files: serve them from a cookie-free domain.
Some details changed with HTTP/2 and HTTP/3 (combining many files matters less now), and today we measure with Core Web Vitals. The spirit is unchanged: send less, send it sooner, and don’t make the browser wait. It is the same thinking behind this website’s own perfect Lighthouse scores.
Read the original: Best Practices for Speeding Up Your Web Site, by Yahoo’s Exceptional Performance team (Steve Souders and colleagues).