Core Web Vitals & Lighthouse
Measured in a real browser, not estimated.
Every vitals test runs in an actual Chrome instance in the cloud and produces repeatable, browser-based measurements. Thresholds turn "seems slower" into a Pass/Error result you can alert on.
- LCP, CLS, TBT & TTI - the loading, stability, and responsiveness metrics that drive Core Web Vitals.
- Lighthouse scores - Performance, Accessibility, Best Practices, and SEO on every run.
- Configurable thresholds - a test fails the moment a metric drops below what you define
Lighthouse scores
- Performance
- Accessibility
- Best Practices
- SEO
- 0–49
- 50–89
- 90–100
Core Web Vitals
- LCPTime for the largest visible element to render≤ 2500ms
- CLSUnexpected layout shift while the page loads≤ 0.1
- TBTMain thread blocked by long-running JavaScript≤ 200ms
- TTITime until the page is fully interactive≤ 3800ms
SCHEDULING
Schedule vitals checks based on how fast your pages change.
Run stable pages daily, check fast-moving pages more often, and trigger manual runs right after every release.
Live schedule preview
Today Tue · Jul 28
LiveLive schedule for Tue · Jul 28, running every 24h. 1 passed and 0 failed of 1 checks run so far today. No further checks today.
1 / 1 today · next tomorrow
Locations
Run vitals checks from the regions that matter to your users
Websites can render very differently depending on where they're accessed from. Each vitals test runs from a single location you choose - create one test per region to compare performance across geographies.
- Five regions available - four in Europe, one in North America, with more by request.
- One location per test, set when you create it or from Edit test properties afterward
- Duplicate a test to a second region to spot location-specific regressions
Alarms & Notifications
Alerting that matches your risk tolerance
Set how many recent runs to evaluate and how many failures should trigger a notification. Since vitals runs daily by default, a large failure threshold can delay detection by days - most teams keep it low.
- Evaluation period & failures to alarm - both configurable from 1 to 50 runs.
- Notify by email, Slack, Telegram, Jira or webhooks - sent the moment the threshold is crossed
- Up to 10 custom headers per test - filter TestCLIX traffic out of analytics, allowlist it past bot protection, or test auth and localization.
- Evaluation period:
- 5 runs
- Failures to alarm:
- 2 runs
Recent runs
WHAT'S INCLUDED
Everything you need to track real-world performance
Vitals tests come with everything listed here, included in every plan.
Core Web Vitals & Lighthouse
Track LCP, CLS, TBT, and TTI alongside Performance, Accessibility, Best Practices, and SEO scores - on every run.
Real cloud browser
Every check runs in an actual Chrome instance in the cloud - repeatable, browser-based measurements, not a synthetic estimate.
Flexible scheduling
Run stable pages daily, check fast-moving pages more often, and trigger manual runs right after each release.
Multi-location testing
Choose London, Paris, Frankfurt, Warsaw, or Ohio. Run a separate test per region to compare performance across geographies.
Instant alerts
Email, Slack, Telegram, Jira or webhooks - with a configurable evaluation period and failure threshold.
Custom headers
Attach up to 10 custom HTTP headers per test for analytics filtering, bot allowlisting, or auth testing.
FAQ
Frequently asked questions
Core Web Vitals - LCP, CLS, TBT, and TTI - plus Lighthouse's Performance, Accessibility, Best Practices, and SEO scores, all captured in a real Chrome browser running in the cloud.
LCP ≤ 2500ms, CLS ≤ 0.1, TBT ≤ 200ms, TTI ≤ 3800ms, and each Lighthouse score ≥ 90. Every threshold is editable per test.
Once a day - default at 08:00 UTC, adjustable in 15-minute steps and limited to selected weekdays. You can also disable scheduling and run tests manually, e.g. right after a deploy.
The run moves to Error, and once your configured evaluation period and failures-to-alarm limits are crossed, you get notified by email, Slack, Telegram, Jira or webhook. Acknowledge a known issue to reset the evaluation window.
Each test runs from one location - choose London, Paris, Frankfurt, Warsaw, or Ohio, with more by request - so create a test per region to compare performance across geographies.
Yes, up to 10 per test - useful for filtering TestCLIX traffic out of analytics, allowlisting it past bot protection, or testing authenticated or localized pages.