Get Tracker Watch Lens

See which third-party trackers the page you are reading contacts, who runs them and what each one did, and stop them with one click. Free to use, with public source code (licence). It sends nothing anywhere: no account, no analytics, no server of ours.

Edge and Firefox users: install it from the store with one click. The Chrome Web Store version will be available shortly. Until then, Chrome installs by hand with the steps below. It takes about a minute. The downloads come from the latest release, which also lists SHA-256 sums to check the files.

Install in Chrome or Edge

1. Download the zip and unzip it into a folder you will keep. The browser reads the extension from that folder, so do not delete it afterwards.
2. Open the extensions page: type chrome://extensions in the address bar (edge://extensions in Edge). Browsers do not allow links to these pages, so type or paste it.
3. Turn on Developer mode (a switch at the top right).
4. Click Load unpacked and choose the unzipped folder, the one that contains manifest.json.
5. Pin the icon (the puzzle piece, then the pin) so the button is always in view. Open any news page and click it.

To update: download the new zip, put its files over the same folder and press the reload arrow of the extension on the extensions page. Chrome may show a reminder about developer-mode extensions when it starts; that is normal for a hand install.

Install in Firefox

Open the Tracker Watch Lens page on Firefox Add-ons and click Add to Firefox. Firefox keeps it and updates it for you.

If you would rather try the zip without the store, you can load it temporarily:

1. Download the zip and unzip it into a folder.
2. Type about:debugging#/runtime/this-firefox in the address bar.
3. Click Load Temporary Add-on… and choose the file manifest.json inside the unzipped folder.

A temporary add-on disappears when you close Firefox, so you repeat step 3 after each restart. The store version does not have that limit.

What it does

• Shows, counted in your own browser, which third-party tracking services the page contacted before your first click, which companies run them, what changed after you answered the cookie banner, and how the page compares with our weekly measurement of news sites.
• Blocks, only when you press the buttons at the top of the panel: Block trackers and Block ads. A stricter "site only" level and a one-click pause per site are included.
• Optional, off by default: learn trackers that are on no list from what they do, and reject cookie banners for you. It never accepts a banner and never chooses a paid option.

What it is not

• Not complete protection. A dedicated blocker such as uBlock Origin covers more. Lens's strength is showing you what happens.
• Counts, not verdicts. A request to a tracking service shows that it was contacted, not what was sent or what the company does with it. Our list is limited and some entries are not verified one by one; the panel says which.

Why it asks for access to all websites

To count what a page loads, the extension has to see the requests of every page you open. It reads cookie names and lifetimes but never their values, keeps no browsing history, and sends nothing out. The full text, checked against the code before every release, is the privacy policy. Our guide to browsing with less tracking explains the rest of what you can do, and the Browser check shows what your browser reveals without installing anything.

Check what you installed

The files are built from the public source code by a GitHub workflow, not on a personal computer. Compare the SHA-256 of your download with the sums on the release page: on Windows, certutil -hashfile tracker-watch-lens-chrome.zip SHA256; on macOS and Linux, shasum -a 256 tracker-watch-lens-chrome.zip.

Problems and ideas

Open an issue on GitHub or write to asenjo.jose@hotmail.com. Tell us the browser, its version and the page where it happened.