Privacy Policy – Core Web Vitals Live

Last updated: March 15, 2026

Published copy (HTTPS, for users & store listing):
https://pagespeed-cz.github.io/Core-Web-Vitals-LIVE/privacy-policy.html

Maintainers: docs/privacy-policy.html is generated from this file when you run npm run build, npm run zip, or npm run privacy-page. Edit policy text only here. The popup “Privacy policy” link uses lib/privacy-policy-url.ts — keep that URL in sync with GitHub Pages.

Overview

Core Web Vitals Live is a browser extension that measures and displays real-time Core Web Vitals (LCP, INP, CLS) performance metrics for webpages you visit. Your privacy is important to us, and this policy explains what data the extension accesses and how it is used.

Data Collection

Core Web Vitals Live does not collect, transmit, or share any personal data. All data stays on your device.

What the extension accesses

Data	Purpose	Storage
Performance metrics (LCP, INP, CLS, FCP, TTFB)	Displayed in the HUD overlay, popup, and toolbar badge	Kept in memory and `chrome.storage.local` (per-tab, cleared on tab close)
User preferences (toggle settings, HUD position)	Remembering your configuration	`chrome.storage.sync` (synced across your Chrome devices via your Google account)
Active tab URL and status	Updating the toolbar badge for the current tab	Not stored

What the extension does NOT do

Does not collect browsing history or personal information.
Does not send any data to external servers, APIs, or third parties.
Does not use analytics, tracking, or telemetry of any kind.
Does not inject ads or modify page content beyond its own overlays.
Does not read or access page content such as form inputs, passwords, or cookies.

Permissions

Permission	Why it is needed
`activeTab`	Access performance data on the tab you are viewing
`tabs`	Update the toolbar badge to reflect the current tab's metrics
`storage`	Save your preferences and per-tab metric snapshots
`debugger`	Optionally throttle CPU or network speed to simulate slower devices (DevTools protocol)

The debugger permission is used solely for performance throttling simulation. It is never used to read, intercept, or modify network traffic or page data.

Third-Party Services

The extension does not contact any third-party services automatically. If you click an external link in the UI (for example the project website link), your browser will navigate to that site as usual.

Data Retention

Per-tab metrics are held in memory and storage.local only while the tab is open; they are removed when the tab is closed.
User preferences are stored in storage.sync and persist until you change or remove them.
Uninstalling the extension removes all stored data.

Changes to This Policy

If this policy is updated, the new version will be published at the same URL and the "Last updated" date will be revised.

Contact

If you have questions about this privacy policy, please open an issue on the project's GitHub repository.

This file is generated from PRIVACY_POLICY.md by npm run privacy-page (also run automatically before npm run build and npm run zip). Do not edit docs/privacy-policy.html by hand.