What Is an Email Tracking Pixel?
An email tracking pixel is a tiny, invisible image — typically 1x1 pixel in size — embedded in email messages. When you open an email that contains a tracking pixel, your email client loads the image from the sender's server. This loading event tells the sender:
- That you opened the email
- When you opened it (exact timestamp)
- Your approximate location (from your IP address)
- What device and email client you used
- Sometimes how many times you opened the email
Tracking pixels are used by marketers, sales teams, and newsletter platforms to measure email open rates and optimize campaign timing. They are also used in more concerning ways by data brokers and surveillance-oriented applications.
How Tracking Pixels Work
The HTML code for a tracking pixel looks like
<img src="https://tracker.example.com/pixel.gif?id=UNIQUE_ID" width="1" height="1">
When your email client loads images, this 1x1 transparent image loads from the sender's server. The server logs the request, recording your IP address, timestamp, and the unique ID that identifies you.
Because tracking pixels are invisible and indistinguishable from regular email images, they operate without user awareness unless specifically blocked.
Who Uses Email Tracking Pixels
Marketing platforms: Mailchimp, HubSpot, Klaviyo, Campaign Monitor — virtually all email marketing platforms use tracking pixels to measure open rates.
Sales tracking: Tools like Salesforce, Outreach, and Salesloft let sales representatives know when you have opened their emails.
Newsletter platforms: Substack, Beehiiv, and similar platforms track subscriber engagement.
Surveillance applications: Spy apps and tracking tools marketed to employers or suspicious partners use email pixels to monitor reading behavior.
Data brokers: Some brokers embed pixels in marketing emails to track engagement and confirm email addresses are active.
How to Block Email Tracking Pixels
Apple Mail Privacy Protection (iOS 15+, macOS Monterey+)
Settings > Mail > Privacy Protection > Protect Mail Activity: Enable
When enabled, Apple routes images through Apple's proxy servers, masking your real IP and pre-loading images to prevent open timing detection. This is the most seamless protection for Apple device users.
Gmail (Web):
There is no built-in pixel blocking in Gmail web. However:
- Gmail automatically proxies images through Google's servers, which masks your IP but still confirms the open
- The uBlock Origin extension blocks many known tracking domains at the browser level
Outlook
Settings > Mail > External images > Automatically download images: Set to Never or Ask me before downloading
This prevents automatic image loading, blocking pixels until you manually approve image loading for specific emails.
ProtonMail
Blocks all remote image loading by default, showing a prompt before loading. Enable manually only for trusted senders.
Third-party email apps
Most email clients have a setting to block automatic image loading. Find it under Settings > Mail/Messages > Privacy or Images.
The Temp90 Connection
When you use Temp90 for service registrations, you avoid the email tracking that begins the moment you receive the first marketing email. By not giving your real email to marketers, you never receive the tracked emails in the first place.
However, for email you do receive at your primary or secondary addresses, pixel blocking prevents senders from knowing when and where you read their messages.
Frequently Asked Questions
Does blocking images break email functionality?
It prevents viewing inline images in emails. Most email content remains readable. You can manually approve image loading for trusted senders in most email clients.
Do all marketing emails use tracking pixels?
Virtually all professional marketing and sales email platforms include tracking by default. Assuming tracked unless you have specifically blocked it is the safest approach.
Can I detect which emails contain tracking pixels?
Browser extensions like PixelBlock (Chrome) and Ugly Email (Gmail) identify emails containing known tracking pixels and alert you before you open them.
Conclusion
Email tracking pixels are a nearly universal feature of commercial email that silently reports your reading behavior to senders. Blocking them through email client settings (or Apple Mail Privacy Protection) prevents this surveillance while maintaining full email functionality. Combined with using Temp90 for registrations — which prevents ever receiving tracking pixels from many senders — these measures provide comprehensive protection against email-based behavioral monitoring.