Chrome Dependency

The local Lighthouse auditor requires Chrome. Unlighthouse uses an installed browser when available. If no browser exists, Unlighthouse downloads Chrome before the first audit. Later audits reuse that browser.

Select an installed browser

CHROME_PATH=/usr/bin/google-chrome pnpm exec unlighthouse --site https://example.com

Set CHROME_PATH to the executable available on your machine or container. Use CHROME_FLAGS for process arguments. See Chrome Options.

Automatic downloads

Set chrome.useSystem: false to use the downloaded browser. An existing CHROME_PATH takes precedence over this setting. Clear CHROME_PATH to force the downloaded browser. Set chrome.useDownloadFallback: false to require an installed browser. Set chrome.downloadFallbackVersion to select a Chrome build. Set chrome.downloadFallbackCacheDir to select the browser cache directory.

Lighthouse and Puppeteer download as one prebuilt package before the first audit. The dashboard downloads when you open the CLI server or export a static report. These downloads require npm and network access on first use. Cached dependencies work offline.

The CLI excludes Lighthouse's upstream error-reporting dependencies from audit downloads. Lighthouse library audits do not initialize that reporting system. The CLI also excludes source maps, type declarations, unused assets, and translated audit text. CLI audit output uses English. Audit logic remains upstream Lighthouse code. The standalone Core package keeps the dependencies supplied by its host.

Set UNLIGHTHOUSE_RUNTIME_CACHE to select the shared dependency cache. The default follows XDG_CACHE_HOME, or uses ~/.cache/unlighthouse/runtime.

puppeteerOptions.executablePath has no effect on the v1 local auditor.