Privacy policy
Sentinel browser extension. Last updated: 2026-11-13.
Sentinel ("Sentinel — Saved Posts Library") is a browser extension that runs entirely in your browser. We do not operate any server that receives your data, we do not use analytics, and we do not sell, share or transfer your data. This page explains what the extension stores on your device and which network requests it can make.
1. Data stored on your device
- Saved posts library. When you sync, posts you saved or liked on Instagram, Facebook, Threads, X, TikTok and RedNote (link, author, text, media links, dates, your own tags and notes) are stored in your browser's IndexedDB. Optional offline thumbnails are stored the same way. This data stays on this device unless you set the optional send-after-sync endpoint (see section 2).
- Settings. Switches, block lists, favourites and similar preferences are stored in the extension storage (
chrome.storage). If you use Chrome Sync, Chrome itself may sync these preferences between your own devices through your Google account; Sentinel has no access to that. - AI provider keys and chat history. If you add an API key for the AI assistant, it is stored only in local extension storage on this device (never synced) and is sent only to the provider you configured.
- Cookies. Library sync reuses your existing logged-in session in the browser to read your own saved lists, so requests to a social network carry that network's own cookies. The cookie manager lists or edits cookies only when you ask. Cookie values are not copied anywhere else.
You can delete all data at any time by clearing the library in the extension, removing the extension, or clearing site data for the extension.
2. Network requests the extension can make
| Destination | When | What is sent |
|---|---|---|
Public phishing lists on raw.githubusercontent.com (Phishing.Database, MIT licence) | On by default. About once every 24 hours | A normal download request with no cookies. GitHub, as the host, sees your IP address and the request itself. Nothing about your browsing is uploaded; matching is done locally. Can be turned off in Features |
| A phishing-list URL you enter yourself (optional, empty by default) | About every 12 hours, only if you enter an address | A normal download request with no cookies; that server sees your IP address |
| The AI provider you configured (Anthropic, OpenAI or Google) | Only when you use an AI feature (translate, summarize, chat) | The text you ask it to process (for example the selected text, a RedNote note you asked to translate, or your chat message) and your API key. The provider's own terms and privacy policy apply |
| Instagram, Facebook, Threads, X, TikTok, RedNote / Xiaohongshu | When you sync your library, download media or use on-page tools | Requests those sites would receive from your logged-in browser anyway, to read your own saved lists and media or to perform actions you started |
| Social-network image and video servers (CDNs) | Whenever you open the library: thumbnails and media are loaded directly from the network that hosts them. An offline copy of thumbnails is only a fallback and is off by default | A normal image request. The CDN can see your IP address and which items you are viewing |
| Media servers of those networks (downloader) | When you download media or add it to the bulk download queue | A request for the file you chose, with the Referer header the CDN requires |
| Nothing — image text recognition (OCR) runs on your device | When you scan your library for text inside images | No request at all. The OCR engine and its language model ship inside the extension, so your images are never uploaded |
| The image address you choose to save in another format (utilities) | Only when you use "save image as" from the context menu | A normal request, with your cookies for that site, to the host serving the image; the result is saved to your downloads. Nothing is sent anywhere else |
| An endpoint you type yourself (optional library "send after sync" setting; optional, off by default, empty URL = disabled) | After each sync, only if you configure an address. Items that were updated since the last successful send are sent again | An HTTP POST to the URL you typed (any address, local or remote) with your bearer token, containing for each new or updated item: platform, kind (saved/liked), id, uid and link; author handle, name and profile link; post text; your own private note, tags and collection names; like/comment/share/view counts; post, saved, first-synced and last-synced timestamps; and the type of each media file (image or video, not the media itself). You are responsible for the receiving server |
3. What we do not do
- No analytics, telemetry, advertising identifiers or crash reporting.
- No remote code: all code ships inside the extension. Only data (the phishing domain list) is downloaded.
- No sale or sharing of data with third parties by us (the destinations in the table are contacted directly by your browser, as described), and no use of data for credit or lending decisions.
- Your browsing history is not collected or sent anywhere.
4. Permissions
If you turn on "Global Privacy Control", the extension registers, at runtime and only while that option is on, a small content script (privacy-gpc) on web pages that sets the GPC signal. It is removed when you turn the option off.
Every permission the extension requests and the reason for it are listed on the Permissions explained page.
5. Children
Sentinel is not directed at children under 13 and does not knowingly collect any personal information.
6. Third-party names
Instagram, Facebook, Threads, X, TikTok and RedNote/Xiaohongshu are trademarks of their respective owners. Sentinel is not affiliated with or endorsed by them.
7. Changes and contact
If this policy changes, the new version is published at this address with an updated date. Questions: dinvvan@gmail.com.