Faster websites, with the receipts
Learn what actually makes websites faster. Proven on real sites, explained in plain language, by the team building Calibre.
Every post goes out on the RSS feed the day it is published.
Web Performance
It’s official: Airline websites are slow, but they don’t have to be
Ben Schwarz
Start here
Inside Calibre
Delivering a dynamic hexagonal world map in just 10kb
Ben Schwarz
Web Performance
10 Causes of Slow Websites (and How to Fix Them)
Karolina Szczur
Inside Calibre
We needed a screenshot pipeline; we got a design QA tool instead
Ben Schwarz
Web Performance
Profiling React component performance with DevTools
Ben Schwarz
Guides
All posts
Core Web Vitals
Metrics and scores
Fixing slow pages
Keeping sites fast
Changelog
Test your own pages
Two free tools, no sign-up.
Core Web Vitals Test
Check whether your site passes Google’s Core Web Vitals assessment, using Chrome UX Report data from real visitors.
Check Core Web Vitals →
Website Speed Test
Run a Lighthouse audit on any page from the test location and device you choose, and see exactly what is slowing it down.
Test your site →Fast website, happy customers
See it? Fix it. Start improving UX & performance today.
