Stop email trackers and hidden read-receipts

A large share of marketing and newsletter emails quietly report back the moment you open them. They do it with a tiny invisible image, and the fix is mostly a single setting in your mail app. This guide explains how the tracking works and gives you the exact steps to switch it off in Gmail, Apple Mail, Outlook, and Proton Mail.

How a tracking pixel works

A tracking pixel (also called a spy pixel) is a tiny image, often just one transparent dot, embedded in an email and hosted on the sender’s server. Your mail app cannot show that image without fetching it from that server. The moment it does, the sender’s server logs the request.

From that single fetch, the sender can learn:

• That you opened the email, and often how many times.
• Roughly when you opened it, which for a marketer signals you are active and worth chasing.
• Your approximate location and device, inferred from the IP address your app used to fetch the image.

None of this needs your consent or any click. It is simply the side effect of your app automatically loading remote images. Block that automatic loading, or route it through a privacy proxy, and the pixel goes dark. The same trick also defuses “read receipts” that some senders bolt onto ordinary mail.

Gmail

Gmail loads external images by default, though it serves them through Google’s own proxy, which hides your IP and device from the sender. That blunts location tracking, but the sender can still see that the message was opened. To stop images loading automatically:

1. Open Gmail on the web and click the gear icon, then See all settings.
2. On the General tab, scroll to the Images section.
3. Select Ask before displaying external images (instead of “Always display external images”).
4. Scroll down and click Save Changes.

From now on, images (and pixels) stay unloaded until you click Display images below on a message you trust. In the Gmail mobile apps, open Settings, choose your account, and set Images to Ask before displaying external images.

Apple Mail and Mail Privacy Protection

Apple’s Mail Privacy Protection (MPP) takes a different, clever approach. Instead of blocking images, it routes them through Apple’s servers, which preload and cache remote content at random times. The sender sees a fetch that came from an Apple proxy, at a time unrelated to when you actually read the mail, from an IP that masks your real location. In effect, open tracking becomes noise.

It works for any account you read in Apple Mail, including Gmail or Outlook accounts. To turn it on:

• iPhone or iPad: Settings, then Apps, then Mail, then Privacy Protection, and turn on Protect Mail Activity.
• Mac: open Mail, then Settings, then Privacy, and tick Protect Mail Activity.

If you ever turn Protect Mail Activity off, you can still keep Hide IP Address enabled to mask your location. MPP is genuinely effective against pixel tracking, so leaving it on is a sensible default.

Outlook

The path depends on which Outlook you use.

Classic desktop Outlook (Windows):

1. Go to File, then Options, then Trust Center, then Trust Center Settings.
2. Open Automatic Download.
3. Keep Don’t download pictures automatically in standard HTML email messages ticked.

Images then stay blocked until you choose Download Pictures on a specific message.

New Outlook for Windows and Outlook on the web: open Settings, then Mail, then look under the external-content controls (Microsoft has been rolling out clearer options through 2026) to block external images by default. On the Outlook mobile apps, open your account settings and turn on Block External Images.

Proton Mail

Proton Mail ships with tracker protection enabled by default, so much of this is handled for you. It removes known trackers from incoming messages and preloads remote images through a proxy with a generic IP address, so senders cannot see when you open mail or where you are. On the web app it also strips known tracking parameters (such as UTM tags) from links inside your emails.

The setting lives in Proton Mail under Settings, then Email privacy. Note that it is set per device rather than synced, so check it on each app you use. If you use a privacy-first provider like Proton, most of this guide is already done.

One extra habit: strip tracking links

Pixels are not the only tracker. Many links in marketing mail carry parameters like ?utm_source= or long tracking codes that identify you when clicked. A couple of easy habits help:

• Prefer providers or tools that strip these automatically (Proton Mail does this on the web app).
• When you must click, you can often delete everything from the ? onwards in the address bar and still reach the page.
• Avoid clicking “unsubscribe” in obvious spam; that click itself confirms your address is live. Use your mail app’s own block or report-spam button instead.