DebugBear alternative
Calibre vs DebugBear
Real User Monitoring is included on every Calibre plan, from $75 a month, alongside Google CrUX data and Lighthouse tests.
Free for 15 days. No credit card required.
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How Calibre and DebugBear differ
Updated
| Feature | ||
|---|---|---|
| Real User Monitoring | ||
| Included from | $125 a month, on Startup | $75 a month, on Starter |
| Sample a share of visitors | Team plan and up | Every plan |
| Synthetic Monitoring | ||
| Synthetic tests on the Team plan | 10,000 a month for $325 | 15,000 a month for $150 |
| Synthetic test history | Kept for 3 to 24 months, by plan | Kept for the life of your account |
| Plans and pricing | ||
| Seats on the cheapest plan | 1, on the $69 Intro plan | 3, on the $75 Starter plan |
| Access and automation | ||
| SAML single sign-on | Custom plans only | Self-serve on the $150 Team plan, with SCIM |
Calibre and DebugBear both include
- Real User Monitoring
- Google CrUX data
- Scheduled synthetic tests with Lighthouse
- Performance budgets
- Pull request reviews
- 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 DebugBear
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’s RUM dashboard was instantly attractive thanks to the negligible impact on page weight, support for CWV, and thoughtful metrics presentation.”
Real User Monitoring
Real user data that points to the fix
See which pages are slow for real visitors, which element is to blame, and how each release changed things.
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 →A 9 KB, secure and privacy-first script
The script is signed, so supporting browsers won’t run it if it has been tampered with. It uses no cookies or localStorage and collects no personal data.
Learn how RUM protects visitors →See the impact of every release
Calibre marks production deploys from GitHub automatically, and compares each release with the one before, for real visitors and in Lighthouse tests.
Learn about deploy tracking →Questions about switching from DebugBear
Does Calibre have Real User Monitoring?
Yes. Calibre RUM is included on every plan. It measures LCP, INP, CLS and TTFB, breaks LCP, INP and TTFB into subparts, and points to the element behind LCP, CLS and INP. You can segment by page, device, browser, country and deployment.
How does Calibre’s pricing compare with DebugBear’s?
Calibre starts at $75 a month with Real User Monitoring, CrUX data and synthetic tests included. DebugBear’s published pricing (October 2026) started at $69 a month without RUM, with RUM plans from $125. Calibre’s $150 Team plan includes 15,000 synthetic tests a month; DebugBear’s $325 Team plan includes 10,000. Calibre counts Real User Monitoring by sessions, not page views, so a visitor who browses ten pages in one tab counts once.
Is Calibre a good DebugBear alternative?
Yes, if you want Real User Monitoring on a lower-priced plan. Calibre includes RUM, CrUX data and Lighthouse tests from $75 a month, keeps test history for the life of your account, and offers SAML single sign-on on the $150 Team plan.
Does Calibre support SSO, SCIM and audit logs?
Yes. SAML single sign-on with SCIM provisioning is self-serve on the Team and Company plans, and you can require SSO for everyone. The Company plan adds a security audit log of sign-ins, member changes and API key activity, which you can stream to your SIEM.
How do I switch from DebugBear to Calibre?
Add your Sites to Calibre. It finds your key pages, pulls their CrUX data and starts Lighthouse tests straight away. Then add Calibre’s RUM snippet in place of DebugBear’s, recreate your budgets, and connect GitHub and Slack. Or book a setup call and we’ll do it with you.
Can I try Calibre before switching?
Yes. Start a free 15-day trial, no credit card required, and run Calibre alongside DebugBear 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.
