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Lighthouse 3.0 is out! 3.0 features faster audits, less variance, a new report UI, new audits, and
How to update to 3.0
CLI. Run npm install -g lighthouse@next.
Node. Run npm install lighthouse@next.
Chrome Extension. Your extension should auto-update to 3.0.
Chrome DevTools. Lighthouse 3.0 will be available in Chrome 69.
Faster audits and less variance
Lighthouse 3.0 completes your audits faster, with less variance between runs, thanks to a
Simulated throttling. Previously Lighthouse actually throttled your page before running
audits. Now, Lighthouse uses a new internal auditing engine, codenamed Lantern, that runs your
audits under your normal network and CPU settings, and then estimates how long the page would
take to load under mobile conditions.
Smaller waiting periods. To determine that a page has finished loading, Lighthouse
needs to wait for the network and CPU to have no activity. This waiting period is smaller in v3.
New Report UI
Lighthouse 3.0 features a brand-new report UI, thanks to a collaboration between the Lighthouse
and Chrome UX (Research & Design) teams.
The Node version of Lighthouse now supports the same configuration options as the CLI version.
This could be a breaking change, depending on how you configured your Node Lighthouse module in
v2. See Invocation changes for more information.
In Lighthouse 3.0 the scoring model for Performance audits changes. A score of 50 represents
the 75th percentile, and a perfect score of 100 represents the 98th percentile, which is the point
of diminishing returns.
The Performance score is a weighted average of the Performance audits. The weighting of the
audits also changes in v3.
First Contentful Paint (New in v3)
First Meaningful Paint
First CPU Idle (First Interactive in v2)
Time To Interactive (Consistently Interactive in v2)
Perceptual Speed Index
Estimated Input Latency
Going forward, the Lighthouse v3 Scoring Guide is the source of truth for anything
you need to know regarding how scoring works in Lighthouse v3.
New output formats and changes
CSV output support
Report results can now be output in CSV. Each row contains information and results for one
The name of the category that the audit belongs to.
Improve your load performance by adding rel="preconnect" attributes to link tags, which informs
the browser to establish a connection to an origin as soon as possible.
See Preconnect to learn more.
First Interactive ➡ First CPU Idle
The First Interactive audit has been renamed to First CPU Idle to better describe how it
works. The general purpose of the audit is the same. Use this audit to measure when users are
first able to interact with your page.
Perceptual Speed Index ➡ Speed Index
In Lighthouse 3.0 the Perceptual Speed Index audit is now Speed Index. This change aligns
Lighthouse with how WebPageTest measures this metric. The purpose of the audit
is the same, but the underlying metric is slightly different.
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