Privacy Policy

Comprehensible Input Monitor is a Chrome extension and companion web app for tracking how much language input you get from YouTube videos. This page describes what the extension and web app collect, how it is used, and where it is stored.

Last updated: May 9, 2026. Contact: claude@lenza.org.

What The Extension Collects

When you watch a video on YouTube (or a page that embeds a YouTube player), the extension records a watch session. A session can include the video title, channel name, source URL, canonical content URL, language-classification result, start and end time, and watched seconds. The extension only acts on pages whose URL is on youtube.com or youtube-nocookie.com; on other pages it does nothing.

What The Extension Stores Locally

The extension keeps your watch history, daily totals, your sync configuration, and a short log of recent API requests in Chrome extension storage. This data stays in your browser unless you configure Web Sync. The API token, if you set one, is visible in the extension popup during this private beta so testers can verify setup.

What The Web App Stores

When Web Sync is configured, tracked sessions are sent to the web app you point the extension at and stored in a Postgres database. The app stores enough content metadata (title, channel, canonical URL, language tags, watched seconds) to group repeated watches of the same video and show progress over time. You control which server the extension syncs to.

What We Do Not Do

We do not sell your data. We do not share it with third parties. We do not use it for advertising. The extension does not read or modify pages outside of YouTube, does not track your browsing on other sites, and does not collect form input, passwords, or financial information.

Permissions Used

The extension requests storage to keep your local watch history; activeTab and scripting to read player state on the tab you are watching; host access to YouTube domains so it can read player metadata; and host access to the configured sync server so it can POST your watch sessions there. The default sync server is https://comprehensible-input-monitor.onrender.com; localhost is also permitted for development. Content scripts only run on YouTube domains.

Private Beta Expectations

This is an early private beta shared by invitation. Please only install it if you are comfortable with the extension collecting watchtime and video metadata for the purpose of testing comprehensible-input progress tracking. You can uninstall the extension at any time from chrome://extensions; doing so removes all locally stored data.