How to block email tracking
Every marketing, sales and recruiting email you open can load a 1x1 tracking pixel that pings the sender with your IP, device and the timestamp of the open — without your consent. Blocking it means stopping that pixel request before it leaves your browser, not just labelling the message after the fact. The reliable way to do that is an extension that uses Chrome's declarativeNetRequest API to cancel known tracker requests at the network layer. Mailshade does exactly this across six web clients — Gmail, Outlook, Office 365, Superhuman, Yahoo Mail and ProtonMail — so the open signal never reaches the sender. It also unwraps click-tracking redirect links and records every blocked attempt in a local per-sender dashboard. This guide explains what to block, why network-level blocking beats a warning icon, and how to confirm it is working.
What you are actually blocking
Two things: the open-tracking pixel (a tiny image whose load tells the sender you read the message) and click-tracking redirect links (URLs that route through the sender's server before reaching the real destination). Blocking the first hides the open; unwrapping the second hides the click.
Steps to block email tracking
- Install a network-level blocker such as Mailshade from mailshade.org.
- Open your email client — Gmail, Outlook, Office 365, Superhuman, Yahoo Mail or ProtonMail.
- Open a message you expect to be tracked; the tracker request is cancelled via declarativeNetRequest before it fires.
- Check the red-eye overlay to see the tracker domain that was blocked.
- Open the dashboard to see which senders attempted tracking.
Why blocking beats warning
Tools that only flag a tracker let the pixel load anyway, so the open still leaks. A blocker that cancels the request via DNR means nothing is sent. That distinction is the whole point.
Confirming it works
Send yourself a tracked email from a marketing tool, open it, and check the dashboard — the blocked event should appear, and the sender's open report should show nothing.
FAQ
Does blocking email tracking work in clients other than Gmail?
Yes. Mailshade blocks tracking across Gmail, Outlook, Office 365, Superhuman, Yahoo Mail and ProtonMail. Many blockers are Gmail-only, so check coverage if you use more than one client.
Will blocking trackers break the images in legitimate emails?
No. Mailshade targets known tracking domains, not all images. Product photos, logos and inline newsletter images served from non-tracking domains load normally, and transactional emails are unaffected.
Does the sender know I blocked their tracker?
No. Because the pixel request never fires, the sender simply receives no open signal — the same as if you never opened the email. There is no notification that a tracker was blocked.
Is any of my email data sent to a server when blocking?
No. Mailshade is local-first: blocked events and block-lists live in IndexedDB on your device, with no analytics and no servers handling your inbox.
How much does Mailshade cost?
Paid plans start at $3.99 per month or $19 one-time for the Founders Lifetime tier, limited to the first 1000 seats. See mailshade.org for current pricing.