Web performance monitoring your whole team can act on
Track real user experience, Google’s Core Web Vitals data, and scheduled synthetic page speed tests — all in one platform.
Trusted by teams at
Three data sources. One platform. The full picture.
See what real users experience, how Google assesses your site, and exactly what’s slowing pages down.
Track live user sessions with RUM
Collect Core Web Vitals from real browser sessions on your websites. Lightweight, privacy-first, and ready in minutes.
Learn about Real User Monitoring →
See what Google sees
Track Google’s search site speed ranking CrUX dataset for every site you monitor.
Learn about CrUX Monitoring →
Synthetic testing to zero in
Iterate from good to great with lab data that surfaces the exact issues your users are facing and validates your fixes.
Learn about Synthetic Testing →Focus on what matters most.
Calibre surfaces the highest-impact issues and helps your team act on them. Less time digging through data, more time making your sites faster.
Your sites, ranked, assessed and checked
Get organised with Calibre monitoring. Get clear visibility of all your sites, ranked by performance.
Get started with Calibre →
Clearly see Third Party impact
Detailed Third Party impact analysis helps you understand how external resources affect site performance.
Learn about Third Party tracking →Pass Google’s Core Web Vitals evaluation
Calibre automatically collects the site speed data Google search rankings uses. See which pages pass Core Web Vitals and which don’t
See how CrUX monitoring works →
Surface the worst user interactions delays with RUM
Identify and assess the slowest key interactions on your site with Calibre RUM’s INP Attribution Targets.
Learn about RUM element attribution →“Calibre delivers the substance behind the statistics. They know the actionability of performance measurement is paramount.”
“Thanks to detailed page breakdowns and filtering, I’ve found performance issues way deeper into customer journeys than I’ve seen before.”
“Thanks to Calibre’s reporting, we were able to detect a massive downgrade in performance.”
“Now we can provide our clients with solutions, instead of setting up our own tooling.”
“Guaranteeing our clients good performance and delivering best practices has never been easier for us.”
Built for the way your team works.
Whether you’re optimising for SEO, managing client sites, shipping product, or building the infrastructure — Calibre fits your workflow.
SEOs
Meet and maintain Core Web Vitals with ease. Track the data Google uses for rankings and get alerted before metrics slip.
Calibre for SEOs →Agencies
Make speed a competitive advantage. Monitor all your client sites, benchmark competitors, and report on progress with confidence.
Calibre for Agencies →Product Teams
Give your customers fast, reliable experiences. Make performance part of your product development process.
Calibre for Product Teams →Developers
Integrate with Calibre to create custom solutions and workflows. CLI, Node.js API, PR Reviews, CI/CD integration & more.
Calibre for Developers →Fits into the tools you already use.
GitHub
Get performance data in your pull requests.
Slack notifications
Send alerts to a Slack channel.
Zapier
Forward Calibre data and alerts to 5,000+ services.
Netlify
Mark deployments on charts and trigger tests.
Render
Test against deployment environments.
Webhooks
Send performance data to your own systems.
Node.js API
Build integrations and automate fetching data.
Command line interface
Manage monitoring from your terminal.
See your first results in minutes
Start a free 15-day trial. No credit card required.
