Leverage a modern testing suite

Built on a custom set of tools, powered by Google Lighthouse, Calibre provides comprehensive page speed recommendations and makes it easy to identify bottlenecks.

Automated monitoring

Calibre schedules automated web page performance tests for your sites, offering a granular timeline of performance history. Test using either our command line or Node.js API as a part of continuous deployment process.

Device and condition emulation

Device, bandwidth and CPU simulation has never been easier. Experience and track real-world conditions under which customers browse your sites.

Metric budgets and alerts

Set attainable budgets for crucial metrics. Calibre will notify your team when budgets are exceeded or met via email and Slack.

Companies testing and improving web performance everyday

...and many more.

How does Calibre work?



Calibre tests your site without tracking codes or JavaScript unnecessarily slowing down apps.
Simply add pages to monitor.



Our managed agents test using desktop, or emulated device and connection profiles. We’ll record everything your customers see under these conditions.



Deep-dive into the state of your apps’ performance with screenshots, visual completion videos and in-depth analysis.



Calibre is built with collaboration in mind, providing instant performance alerts through email, Slack or webhooks.

What our customers are saying

“Calibre lets us know about regressions in our front-end tooling and asset delivery pipelines during ongoing development work.”

John Barton, VP of Engineering at 99designs

Try Calibre for free

Nothing to install · 15-day free trial · Cancel anytime · Set up in minutes.