Privacy policy
Last updated: July 2026
What we collect
Nothing. CWV Drift Monitor does not collect, transmit, store, or share any personal information, browsing history, or user data of any kind. There is no account, no signup, and no analytics.
How the extension works
The extension operates within your browser using native browser APIs:
- The PerformanceObserver API measures layout shift (CLS), interaction latency (INP), and largest contentful paint (LCP) on pages you visit.
- Metric readings are stored temporarily in chrome.storage.local, a sandboxed local storage area accessible only to this extension, on your device.
- Stored metric data is cleared automatically when you close a tab or navigate away.
The one external request
When you open the extension popup, CWV Drift Monitor requests mobile and desktop performance scores from Google’s PageSpeed service at pagespeed.web.dev. This is the only network request the extension makes, and it is triggered by you opening the popup, never in the background.
That request contains the URL of the page you are currently viewing, because a performance score cannot be produced without it. It contains no identifier for you, your browser, or your device. Google’s handling of that request is governed by Google’s privacy policy.
If you do not open the popup, no external request is made.
Permissions used
- activeTab. Reads performance metrics from the page you are currently viewing, and retrieves its URL for the score request.
- scripting. Injects the PerformanceObserver content script into the active tab.
- storage. Temporarily caches metric readings and scores so the popup displays instantly on open. All data is local to your device.
- host_permissions for pagespeed.web.dev. Allows the score request described above. No other hosts are requested.
These are the minimum permissions required for the extension to function.
Third-party services
Beyond the PageSpeed score request described above, CWV Drift Monitor makes no requests to any third-party service. There are no analytics platforms, no CDN dependencies, no remote code, no telemetry, and no advertising integrations.
Data retention
Metric data in chrome.storage.local is scoped to individual browser tabs and removed automatically when a tab is closed or navigated away from. No data persists between browser sessions.
Children’s privacy
This extension is a developer tool and is not directed at children. It does not knowingly collect information from anyone under the age of 13.
Changes to this policy
If this policy changes, the updated version will be published at this URL with a revised date at the top.
Contact
Questions about this policy can be directed to:
info@manueltechnologies.com
Manuel Technologies