What is Calibre?

Monitor performance of your apps and sites through the eyes of your users


Track what your users see and feel with continuous and comprehensive performance monitoring.


Receive actionable alerts so your team can act instantly as bottlenecks occur.


Improve performance issues and ship stellar user experiences with key data under your belt.

Essential metrics

Speed Index, time to reach visual completeness, server response, the size and affect assets or scripts have on your sites are no longer a secret.

Visually assess results

All performance data is visualised, so you can easily get a grasp on the state of frontend performance even without digging deep into analysing the numbers.

Automate snapshots

Calibre checks sites every day, offering a granular timeline of performance history. Snapshots can also be triggered manually or through the API as a part of deployment process.

Get notified about victories and bottlenecks

Setting performance budgets will enable real time notifications through email, Slack or webhooks. Always be in the know on how sites are performing and react instantly when problems arise.

Improve team collaboration and transparency

Calibre is built with collaboration in mind—invite as many people as you want with no additional cost. Solve issues more quickly and share metrics with customers.

“Calibre is great for engineers and marketers alike. It 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

These companies are using Calibre to improve performance everyday