Website performance monitoring

Catch website performance regressions before they become the new normal.

Use controlled browser checks to track page-load behavior over time, understand what is consuming bandwidth and CPU, and see when a meaningful regression appears.

Free check · No signup required

Real Chromium runsMain-thread attributionRegression baselines

Why it matters

A single speed test cannot tell you when performance changed.

One-off page-speed tests are useful for diagnosis, but production websites change constantly. New scripts, images, tags, plugins and deployments can alter load behavior after the test is forgotten. Performance monitoring turns those isolated measurements into a time series.

SiteState runs controlled synthetic browser checks and stores the metrics and resource evidence needed to compare current behavior with recent baselines. When performance deteriorates, the regression engine can surface the change instead of asking you to discover it manually.

What SiteState monitors

Performance evidence that explains more than a score

Synthetic browser monitoring

Run repeatable Chromium page loads in a controlled desktop profile so results can be compared over time.

Page-experience metrics

Track synthetic LCP, CLS and Total Blocking Time together with load timing and First Contentful Paint where available.

JavaScript CPU attribution

See which first-party and third-party scripts account for sampled main-thread CPU and estimated blocking impact.

Resource blocker analysis

Classify render-blocking, LCP-critical, bandwidth-heavy and third-party resources and surface the highest-impact opportunities.

Page-weight tracking

Track transferred bytes and resource counts so growth in page weight becomes visible instead of silently accumulating.

Regression engine

Compare recent synthetic results with historical baselines and record sustained warning or poor performance as a regression.

Built for real workflows

Useful when website speed can change without warning

Tag-heavy marketing sites

See when analytics, advertising or third-party widgets add CPU time, blocking work or extra network weight.

WordPress and ecommerce sites

Track performance as themes, plugins, apps, images and content evolve over time.

Teams shipping frequently

Use continuous history to see whether a deployment coincides with a meaningful performance change.

State, not metrics

Measure the state of performance, then explain the direction.

SiteState does not reduce browser performance to one arbitrary grade. It keeps the underlying metrics, blocker evidence and regression history so you can distinguish a noisy test from a persistent change.

The Benchmark Engine can also compare compatible synthetic measurements with a growing reference population. Percentiles are shown only when the cohort has enough samples; SiteState does not fabricate rankings while the benchmark is calibrating.

Run a real website check

FAQ

Questions people ask before choosing a monitoring tool

What is synthetic website performance monitoring?

Synthetic monitoring loads a website in a controlled browser environment on a schedule. Because the test profile is repeatable, teams can compare metrics and page-load evidence over time.

What performance metrics does SiteState measure?

SiteState synthetic checks can measure LCP, CLS, TBT, FCP, load timing, transferred bytes, resource counts, sampled JavaScript CPU and third-party JavaScript CPU.

Can SiteState identify what is slowing a page down?

Yes. SiteState analyzes resource blockers and browser main-thread activity to identify render-blocking, bandwidth-heavy, LCP-critical and CPU-heavy resources and scripts.

How does SiteState detect a performance regression?

The regression engine compares current synthetic behavior with recent historical baselines and tracks sustained violations and recoveries rather than treating every noisy test as an incident.

Free performance tools