About Calibre
Calibre is a web performance monitoring service. It combines real visitor data, Google's Chrome UX data and synthetic page speed tests in one place.
What it does
Calibre measures Core Web Vitals from real visits with a small script. It also reads Chrome UX Report data for any public site, which is useful for comparing with competitors. Synthetic tests run on a schedule to give a steady baseline. Deploy markers show which release changed a metric, and budgets send alerts when a page goes over its target.
Key features
- Real user monitoring of Core Web Vitals
- Chrome UX Report data for any site
- Synthetic tests for steady baselines
- Deploy tracking to see which release changed performance
- Performance budgets with Slack, email and webhook alerts
Who it's for
Web developers, front end teams and site owners who care about page speed and want to connect speed changes to their releases. Teams that compare their site with competitors may also use the public data.
Pricing and good to know
A free trial is offered, along with a free one-off Core Web Vitals report and a set of free tools. The real user monitoring script is small and privacy-first, according to the site.
Highlights
- Real user monitoring of Core Web Vitals
- Chrome UX Report data for any site
- Synthetic tests for steady performance baselines
- Deploy tracking to see which release changed performance
- Performance budgets with Slack, email and webhook alerts
