PostfachRead your mail without being counted.
Most newsletters, and many ordinary messages, carry a picture you cannot see. When your mail program loads it, the sender learns that you opened the message, when, and from where. Postfach takes the known ones out before a message is shown, also when you let the message load its pictures.
What a tracking pixel is.
A picture one pixel wide and one high, or of no size at all, fetched from the sender's mailing service at an address made for you alone. The moment it is loaded, the service knows that this copy of the message was opened, at what time, and from which internet address. Nothing shows on the page.
It is the rule rather than the exception. In the mailbox Postfach was measured against, of some 15,000 messages that fetch a picture from a server, seven in ten carried a known service's tracker or an invisible picture.
- Invisible: a pixel, or no size at all
- An address with a token that stands for you, or for your copy of the message
- Put there by the mailing service, in newsletters and in receipts alike
What Postfach takes out.
Before a message is shown, Postfach reads its HTML and removes the pictures that are there to count you: those of 319 mailing and tracking services it knows by name, and invisible pictures from anywhere. It does so whether the message's pictures load or not, so the trackers are gone before you decide anything. The header of the message says how many were blocked, and whose.
- A list of 319 services that comes with the app, and that a file can bring up to date
- Invisible pictures from any sender, at most a pixel wide and a pixel high
- What is there to be seen stays: spacer lines, and a logo hidden for dark mode
- A struck-through eye and “2 trackers blocked” under the sender
- The same when a message is printed
“Load remote images” means pictures, and nothing else.
Until you allow it, a message loads nothing from anywhere. When you do allow it, for one message, for a sender, or for an account, Postfach lets pictures through and nothing more: no remote stylesheets, no fonts, no media. The listed trackers stay blocked then too, wherever the page names them.
- Remote images wait for your click, and in Junk they always do
- Scripts in mail never run
- Each message gets a cookie store of its own, forgotten with it
- No read receipts: Postfach has no code that sends one
- Links open only on your click; a message cannot redirect or send a form
What was blocked, and what you decide.
Settings › Privacy counts the trackers Postfach took out of the mail you opened and names the services they belong to, the ones found most often first. A message is counted when you open it, and once. Each service has a switch: turn one off and its pictures are left alone, when it took out a picture you wanted to see, or for a mailing of your own whose opens you want to count. The switches are this device's alone, and no settings file carries them.
- Trackers blocked, in how many messages, and since when; Reset Count… begins again
- All Known Services…: every name on the list, with a search and a switch for each
- Your Own Entries: a domain you name is blocked in every message, with every address under it
- Invisible pictures from senders on no list are counted too and have no switch: they always go
- Load remote images and Remember senders, for each account, are here and no longer in Appearance
The list, and a newer one.
The list of known services comes with the app: About This List… in Settings › Privacy says how many services it names, when it was last changed, and what it began with. Between two versions of the app a newer list stands here, as a file. Download it, choose Update List from File… in Settings › Privacy, and Postfach shows what the file would add before it adds anything.
The list of 8 October 2026 → It names 319 services and is the list Postfach 1.6.1 comes with, so for now the file adds nothing.
- Postfach never fetches the list: your browser downloads the file, and you choose it
- A file only adds. Nothing the app blocks is taken away by one, so no file can let a tracker through
- Use the Built-in List takes an update out again
- Plain JSON, for anyone to read: each service's name and the addresses it is known by
What it cannot do.
Some mail services hide you by fetching every picture through servers of their own. Postfach runs no servers, so it does not. A picture you do load tells its server the time and your internet address, and a sender who puts your token on a picture you want to see counts you when you load it. That is why Postfach says it blocks known trackers, and not tracking.
- The list comes with the app, and a newer one is a file you hand to it yourself: Postfach never fetches one
- Tracked links are not rewritten yet: a click on one is still counted
- A message you forward keeps its trackers
Good to know.
Nothing leaves your device
The list is in the app, and the filter runs on your Mac, iPhone, or iPad. No message, and no address of a picture, is sent anywhere to be checked.
Built on open work
The list began with MailTrackerBlocker's, a plugin for Apple Mail under an open licence, and grew with what real mail showed. The notice →
Each account its own way
Settings › Privacy says for each account whether remote images load when you ask or always; in Junk they always wait. The trackers are out either way. More about remote images →
Get Postfach.
Mail without the pixels, on Mac, iPhone, and iPad. From the App Store, one purchase for all three.
