What is an email tracking pixel?

A tracking pixel is a tiny, often transparent 1x1 pixel image embedded in an HTML email. When the email is opened, the email client requests this image from a remote server, which then logs data such as the open time, IP address, and device type.

Can I prevent tracking pixels from working?

Yes, you can prevent them from working by disabling automatic image loading in your email client's settings. This prevents the pixel from being downloaded and thus stops it from transmitting data. However, this may affect the visual presentation of your emails.

Does deleting an email remove the tracking pixel data?

No, deleting an email only removes your local copy. Any data collected by the tracking pixel at the time of opening is already logged on the sender's server and remains there.

Do tracking pixels affect email deliverability or cause emails to go to spam?

Tracking pixels do not directly cause emails to go to spam. However, low engagement rates detected by tracking pixels can indirectly harm sender reputation, leading to more emails being flagged as spam by ISPs. Understanding if your emails are going to spam is important.

How do tracking pixels in HTML emails work and can they be removed? - Content - Email deliverability - Knowledge base

Email tracking pixels, also known as web beacons or tracking tags, are tiny, often transparent 1x1 pixel images embedded in emails. Their primary purpose is to collect data on recipient behavior, providing valuable insights for email marketers. While seemingly innocuous, these pixels raise important questions about privacy and data collection for recipients.

The idea behind them is simple: when an email client loads the content of an HTML email, it typically requests all embedded elements, including images. This request to an external server is what triggers the tracking pixel. Essentially, it’s a silent signal sent back to the sender, indicating that the email has been opened.

This mechanism allows senders to gauge the effectiveness of their campaigns, understand engagement rates, and even personalize future communications. However, for recipients, it can feel like an invasion of privacy, as their reading habits are being monitored without explicit consent or immediate awareness.

The mechanics of email tracking pixels

Tracking pixels work by embedding a small snippet of HTML code into the email body. This code references an image file hosted on a remote server. When the email is opened and its content rendered, the email client attempts to download this image from the server. It's during this download request that the server records various pieces of information.

The data collected typically includes the recipient's IP address, the time and date the email was opened, the type of device or email client used (known as the user agent), and sometimes even geographic location. This information is then logged by the sender's email service provider (ESP) or marketing automation platform, associating the open event with a specific recipient.

Example of an email tracking pixel HTML embedHTML

<img src="https://tracking.example.com/pixel.gif?email=user@example.com&campaign=summer_sale" width="1" height="1" border="0" style="display:none" />

Unlike cookies, which are stored in your web browser and can be managed or deleted, tracking pixels transmit data directly when loaded. This means they operate independently of browser settings related to cookies, making them a persistent method for gathering data on email engagement. You can learn more about how email pixel trackers work and how to stop them.

Why email senders use tracking pixels

For email senders, particularly marketers, tracking pixels are invaluable. They provide hard data on who is opening emails, what content resonates, and how subscribers interact with their messages. This information is crucial for optimizing email campaigns, segmenting audiences, and improving overall email deliverability. Without such data, marketers would be largely guessing at the effectiveness of their efforts.

The insights gained help refine content strategies, determine optimal send times, and identify inactive subscribers who might be removed from lists, thereby protecting sender reputation. Accurate tracking of opens and clicks is fundamental to calculating key performance indicators (KPIs) and proving return on investment (ROI) for email marketing programs. It's also an integral part of understanding how to accurately measure email open rates.

On the other hand, many recipients view tracking pixels as an infringement on their privacy. The idea that every email open is recorded and analyzed can be unsettling. This concern has led to a push for greater transparency and control over personal data, driving features like Apple's Mail Privacy Protection (MPP) which aims to mask open rates. Even the simple act of deleting an email does not erase the previously collected tracking data associated with it.

Benefits for marketers

Engagement measurement: Understand how many recipients open emails and when.
Campaign optimization: Refine content, subject lines, and send times based on performance.
Audience segmentation: Identify active vs. inactive subscribers for targeted messaging.
Deliverability insights: Poor engagement can lead to a damaged sender reputation or even a blocklist (or blacklist) listing.

Concerns for recipients

Privacy invasion: Feeling monitored without explicit consent.
Data collection: Uncertainty about what data is collected and how it's used.
Security risks: Potential for malicious pixels or data breaches if not properly secured.
Irreversible tracking: Deleting the email doesn't remove the already recorded open data.

Blocking and removing tracking pixels

For recipients concerned about privacy, the most effective way to prevent email tracking pixels from working is to block the automatic loading of images in your email client. When images aren't loaded, the pixel's request to the remote server isn't sent, and thus, the open isn't tracked. This is a common feature across many email providers.

How to block images in common email clients

Gmail: Go to Settings > See all settings > General. Scroll down to "Images" and select "Ask before displaying external images" or similar. This is also related to the Gmail message 'Images in this email are hidden' feature.
Outlook: Navigate to File > Options > Trust Center > Trust Center Settings > Automatic Download. Here you can uncheck options for automatically downloading pictures in HTML email messages.
Apple Mail: Desktop versions generally block remote content by default. On iOS, you can enable "Protect Mail Activity" and "Hide IP Address" to prevent tracking.
Other clients: Look for settings related to "Privacy," "Security," or "Images" to disable automatic image loading.

While effective for privacy, blocking images can sometimes degrade the email experience, as many emails are designed with visuals in mind. You might miss important context or design elements. An alternative approach is to opt for plain-text versions of emails where available, or to use services that strip out tracking elements before the email reaches your inbox. This helps address whether tracking pixels affect deliverability directly.

It’s worth noting that simply deleting an email will not retroactively remove data that has already been collected by a tracking pixel once the email was opened. The data is logged on the sender's server at the moment the pixel is loaded. Deleting the email only removes your local copy, not the record of its interaction on the sender's end.

Deliverability impact and privacy considerations

While tracking pixels themselves do not inherently cause emails to be marked as spam, the behaviors they track can indirectly impact deliverability. For instance, if a large percentage of recipients in a campaign consistently don't open emails, this low engagement can signal to Internet Service Providers (ISPs) that the content is unwanted, potentially leading to future emails being sent to the spam folder or even earning the sender a spot on a blocklist (or blacklist). It's crucial to understand that tracking pixels don't directly cause emails to be marked as spam.

Email deliverability is heavily influenced by sender reputation, which is built on consistent positive engagement. If pixels reveal a trend of low opens, high unsubscribe rates, or frequent spam complaints, it indicates poor list hygiene or irrelevant content. ISPs use these signals to decide whether an email is inbox-worthy. Maintaining a healthy sender reputation is paramount to ensuring your messages reach their intended recipients, which is why an in-depth guide to email blocklists is so important.

The landscape of email privacy is also evolving, with new technologies and regulations aiming to give users more control. Features like Apple's Mail Privacy Protection (MPP) and Intelligent Tracking Prevention (ITP) are designed to make pixel tracking less reliable by pre-fetching images, making it difficult for senders to accurately determine actual opens. This shift means marketers must adapt their tracking strategies and rely on other metrics, such as clicks, to measure engagement.

Understanding what a tracking pixel is and how to stop email tracking is key for privacy-conscious users. For senders, adapting to these changes and prioritizing audience trust will be critical for long-term success.

Views from the trenches

Best practices

Always offer a plain-text version of your emails for recipients who prefer to avoid HTML and tracking pixels.

Clearly state your privacy policy and data collection practices to build trust with your subscribers.

Focus on engagement metrics beyond just open rates, such as clicks, conversions, and replies.

Regularly clean your email lists to remove inactive subscribers and reduce potential spam trap hits.

Educate your team on how tracking pixels actually work versus common misconceptions to avoid miscommunication.

Common pitfalls

Relying solely on open rates as a measure of campaign success, especially with privacy features like MPP.

Failing to inform recipients about tracking, leading to distrust and potentially increased spam complaints.

Using overly aggressive tracking that collects more data than necessary, which can be perceived negatively.

Not providing an easy way for recipients to opt out of tracking, such as by offering plain-text alternatives.

Ignoring low engagement signals from pixel data, which can negatively impact sender reputation and deliverability.

Expert tips

Consider using click tracking as a more reliable indicator of true engagement in an era of enhanced privacy.

Implement DMARC to protect your domain reputation and ensure only authorized senders are emailing on your behalf.

Leverage server-side logging for interaction data where possible, rather than solely client-side pixel loads.

Regularly monitor your domain and IP for blocklist (or blacklist) listings that could indicate deliverability issues.

Segment your audience based on engagement levels to send more relevant content, improving overall email health.

Marketer view

Marketer from Email Geeks says that some senders make incorrect claims about how tracking pixels are deleted, suggesting they are removed if the email is deleted.

August 5, 2021 - Email Geeks

Expert view

Expert from Email Geeks says that the notion of a pixel being deleted with an email is a misconception about how email tracking functions.

August 5, 2021 - Email Geeks

Navigating email tracking in a privacy-focused world

Tracking pixels are a fundamental component of modern HTML email marketing, offering senders invaluable data on recipient engagement. While they serve a clear purpose for campaign optimization, they also present privacy concerns for recipients.

For senders, understanding how these pixels work, their limitations due to evolving privacy features, and their indirect impact on deliverability is crucial. For recipients, knowing how to block image loading in email clients provides a level of control over personal data and privacy. As the digital landscape continues to prioritize user privacy, both senders and recipients will need to adapt to new methods of interaction and measurement.