Unseen: Email Tracker Blocker

Unseen blocks email tracking pixels in Gmail on the web, so senders can't see when or how often you opened their email. Normal images keep loading, and a small note above each tracked email names the tracking company, with a button to load images anyway.

It runs only on mail.google.com, has no access to other websites and no host permissions, and has no servers, analytics or account. Open source (MIT).

Blocking is free. An optional Pro feature opens tracked links at their real address without contacting the click tracker: 30 days free, then a one-time payment.