The pixel that reports back when you open an email
Most marketing mail carries a hidden 1×1 image. Your mail client requests it the instant the message renders, and that request tells the sender you read it — when, how often, and from roughly where. MailVault finds those beacons and takes them out of the HTML before the message is rendered, so the request never happens.
See it in seconds
Before and after
The same newsletter, rendered twice. On the left the beacon loads and the sender is told. On the right MailVault has already removed it — nothing else about the message changes.
Hi there — here is what you missed this week.
Hi there — here is what you missed this week.
What the tracking code looks like
This is a real shape of beacon, lifted from a marketing template. It is one line, it is invisible, and it is at the bottom of a message you were happy to receive.
<img src="https://mailer.example.com/o/open.php?u=8f21c0&id=a91f&e=you%40yourdomain.com"
width="1" height="1" border="0"
style="display:none;height:1px;width:1px" alt=""><span data-mv-tracker-blocked="Mailchimp" hidden></span>
Note the e= parameter: your
address, in the URL. That is how an open is tied to you and not just to "someone".
What that one pixel tells the sender
- That you opened it And every time you re-open it after that.
- When, to the minute Which also gives away your working hours and time zone.
- Your IP address So, roughly, where you were when you read it.
- Your device and mail client From the user agent attached to the request.
Seeing it is free. Stopping it is Premium.
Every MailVault user gets the warning: a glyph beside the subject, next to the phishing and domain-mismatch icons, that names the tracking company when you click it. Removing the beacon before it loads is part of Premium.
| Free | Premium | |
|---|---|---|
| Tracker detection on every message | Yes | Yes |
| See which company is tracking you | Yes | Yes |
| Beacon stripped before the message renders | — | Yes |
| Applies in the reading pane, threads, chat view and pop-out windows | — | Yes |
Turn it on in MailVault Premium
$4/month or $25/year, with a 14-day free trial on the yearly plan. Premium also covers scheduled backups, cross-account migration, Email Cleanup and Time Capsule.
How MailVault finds them
Known endpoints. MailVault ships a bundled list of nearly 500 open-tracking URL patterns — Mailchimp, SendGrid, HubSpot, Mailgun, Klaviyo, Marketo, Salesloft, Superhuman, Mailtrack, Yesware and hundreds more. It merges the block list from MailTrackerBlocker (the macOS Mail spy-pixel plugin, itself seeded from HEY's and Simplify Gmail's lists) with the public Ugly Email list, and adds the senders both of them predate.
Why not Brave's or Mozilla's list? Those are web tracker lists — the script and beacon hosts a browser blocks on a page. Email open-tracking runs through different endpoints entirely, so the email-specific lists above are the ones that actually catch what arrives in your inbox.
Shape. A beacon that is not on the list still gives itself away: an image
declared 1×1, or hidden with display:none,
or sitting inside a collapsed container. Images you can actually see are left alone.
Request path. Paths that only ever serve beacons —
/open,
/pixel,
/wf/open — are flagged even
from a host nobody has catalogued yet.
All of it locally. The blocklist is bundled with the app and updated in releases. MailVault never fetches a list at runtime and never uploads any part of your mail: an app that phoned a server to ask which pixels to block would have replaced one tracker with another.
Questions
Does blocking break the email?
No. A tracking pixel is invisible by design — removing it changes nothing you could see. Real images, logos and photos are untouched.
What about tracked links?
MailVault's free link-safety scanner already flags links that redirect through a tracking domain, and warns before you open one. Tracker blocking handles the beacons that fire without any click at all.
Can I still see what was blocked?
Yes — the glyph changes to a crossed-out eye and lists every beacon that was removed, with its vendor and URL. The Tracker Blocking screen in Settings also keeps a running count of what has been found in your mail.
Does this work on Windows and Linux as well as macOS?
Yes. It is part of the message renderer, so it behaves identically on all three platforms.
See all features, the pricing, or read the FAQ.