GTmetrix alternative
Calibre vs GTmetrix
See how real visitors experience your site, not only the pages you test. Real User Monitoring is included on every plan, from $75 a month.
Free for 15 days. No credit card required.
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How Calibre and GTmetrix differ
Updated
| Feature | ||
|---|---|---|
| Real User Monitoring | ||
| Data from your own visitors | Not offered, CrUX data only | On every plan |
| Synthetic Monitoring | ||
| Monitored pages | 1 to 50, by plan | Unlimited, on every plan |
| Pull request reviews | Not built in | A synthetic speed report in each pull request |
| Synthetic test history | Kept for 1 to 12 months, by plan | Kept for the life of your account |
| Plans and pricing | ||
| Team seats | 5 extra users, on Expert only | 3 on Starter, 10 on Team, add more any time |
| Alerts and workflow | ||
| Alerts | Email, Slack and webhooks | |
| Deploy tracking | Manual notes | Automatic from GitHub, or by API |
| Access and automation | ||
| API and MCP limits | 10 to 100 credits a day, by plan | No daily credits, on every plan |
| SAML single sign-on | Not in GTmetrix’s docs | Self-serve on the $150 Team plan |
| Command line tool | Not in GTmetrix’s docs | Every plan |
Calibre and GTmetrix both include
- Google CrUX data
- Scheduled synthetic tests with Lighthouse
- Synthetic tests of logged-in pages
- MCP for coding agents
What’s in Calibre
Real User Monitoring
- LCP, INP, CLS and TTFB from your visitors, plus a UX Rating
- Subparts for LCP, INP and TTFB, so you can see which part is slow
- The element behind each slow LCP, CLS and INP
- Split by page, page group, device, browser, OS, country and city
- Every navigation type, including back/forward cache, prerender and soft navigations
- P50, P75, P95 and P98 for every metric
- Compare each deployment with the one before
- No cookies or localStorage, with optional EU and EEA exclusion
Chrome UX Report (CrUX)
- Google’s Core Web Vitals for your origin and each key page
- Pages found automatically by scanning your site
- History from the day you add a Site, charted up to 24 months
- Pass or fail against Google’s Core Web Vitals assessment
- The share of good, needs improvement and poor visits
- LCP subparts from real Chrome users
- UX Rating by country, device and navigation type
- Rank your site against competitors, with nothing to install
Synthetic Monitoring
- A full Lighthouse audit on every test: Performance, Accessibility, Best Practices and SEO
- 17 test locations, 12 device presets and 14 network speeds
- Hourly, daily or custom schedules, plus tests on demand
- Logged-in pages, with login forms, basic auth, cookies or headers
- Performance budgets on any metric, with email, Slack and webhook alerts
- A speed report in every pull request
- Filmstrip, long tasks and third-party impact for every test
- Results kept for the life of your account
Teams and automation
- SAML single sign-on with SCIM, self-serve on the Team plan
- Enforced SSO, verified domains and passkeys
- Audit log streaming to your SIEM, on the Company plan
- Admin, User and Viewer roles
- CLI, Node.js API and GraphQL API on every plan
- An MCP server for Claude Code, Cursor and other coding agents
- Webhooks, plus Slack, GitHub, Netlify and Zapier integrations
- Export metric history as CSV
Switching from GTmetrix
We’ll help you move
Set it up on a call with our founder, or script it yourself. Either way, your Core Web Vitals history is there from day one.
Set up on a call
Book a call with Ben, Calibre’s founder. We’ll add your Sites, recreate your budgets, install the RUM snippet and connect GitHub and Slack with you.
Book a setup call →Script the setup
Create Sites, pages and Test Profiles from code with the Calibre CLI, Node.js API or GraphQL API. This is useful when you have many Sites to move.
Read the CLI docs →Start with your history
Calibre pulls Google CrUX history as soon as you add a Site. Your Core Web Vitals trends are there from the first day, with no wait to build history.
Learn about CrUX Monitoring →“Calibre delivers the substance behind the statistics. They know the actionability of performance measurement is paramount.”
Built for teams
Monitor every page, with your whole team
Share one view of every page, and get an alert in Slack when a page goes over budget.
Find the element that slowed the page
Calibre RUM attributes LCP, CLS and INP to the element that caused them, and breaks INP into input delay, processing and presentation delay.
Learn about Real User Monitoring →Catch regressions in pull requests
Calibre runs synthetic tests on each pull request’s preview deployment and posts a speed report in the pull request, before the change ships.
Learn about pull request reviews →Performance budgets on any metric
Set a budget for any synthetic metric, per page and Test Profile. Get an alert by email, Slack or webhook when it’s at risk or exceeded.
Learn about budgets →Questions about switching from GTmetrix
Does Calibre have Real User Monitoring?
Yes. Add Calibre’s RUM snippet and it measures LCP, INP, CLS and TTFB for your own visitors. It shows which element caused each slow result, and splits results by page, device, browser, country and release. It’s included on every plan, including the free trial.
GTmetrix is cheaper. Why choose Calibre?
Calibre does more than test pages. You get Real User Monitoring, unlimited Sites and URLs, Slack and webhook alerts and pull request reviews. Plans start at $75 a month with 3 seats, or $150 with 10.
Can I monitor more than one site?
Yes. Every Calibre plan includes unlimited Sites and URLs. Plans are priced by Real User Monitoring sessions, synthetic tests and seats, not by the number of pages you monitor.
Can Calibre test pages behind a login?
Yes. Calibre signs in with single or multi-step login forms, basic auth, or cookies and headers you provide.
Can I automate Calibre?
Yes. Every plan includes the CLI, the Node.js API and the GraphQL API, so you can run tests from CI, manage Sites and pull data into your own reports. The Calibre MCP server lets Claude Code, Cursor and other coding agents read your monitoring data.
Can I try Calibre before switching?
Yes. Start a free 15-day trial, no credit card required, and run Calibre alongside GTmetrix while you decide. Synthetic results will differ a little, since each tool tests from its own locations and devices.
Need help to dial in your new speed system?
Our friendly, knowledgeable team will help you establish a system that works efficiently or answer any questions. We’re here to support you in your web performance journey. Contact support.
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Fast website, happy customers
Start a free 15-day trial, or book a setup call and we’ll move you across.
