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It's a tiny little image in your email marketing campaigns. But tracking pixels pack a pretty big punch.

Email marketing is a powerful tool to reach out to customers and promote your products and services. However, to make the most out of your email marketing campaigns, you need to track how your emails perform. This is where tracking pixels come in. In this article, we'll explore what tracking pixels are and how they are used in email marketing.

What is a tracking pixel?

A tracking pixel, also known as a web beacon or a tracking tag, is a small transparent image (often a GIF) embedded in an email. The image is usually only 1x1 pixels in size (literally one pixel), making it virtually invisible to the recipient. When the email is opened, the tracking pixel is loaded from a remote server, allowing the sender to track certain information about the email.

How are tracking pixels used in email marketing?

Email marketers use tracking pixels to monitor the effectiveness of their promotional campaigns. For example, by tracking whether an email was opened or not, email marketers can measure the engagement rate of their campaigns. While clicks in emails are tracked using UTMs and monitoring referral sources in analytics, tracking pixels help measure other metrics that are useful to marketers.

The information that can be tracked by a tracking pixel includes:

• Whether the email was opened
• How long the email was open
• How far down the email a recipient scrolls
• Whether any links in the email were clicked
• The recipient's IP address
• The recipient's email client and device type
• The recipient's location

Tracking pixels can even be used to determine if your subscribers are viewing emails in dark mode.

You can use the information gathered from tracking pixels to optimize future email campaigns. For example, if a particular email has a low open rate, you could try adjusting the subject line or the sender name to improve the chances of the email being opened.

A lot of the information you find in the analytics or reporting from your email service provider (ESP) comes from tracking pixels.

Email marketers can also use these pixels to segment their mailing lists and improve email personalization. This doesn’t mean email marketers are using personal information, but rather that they’re looking at how long each user engages with each part of the email to determine what will be most relevant for each recipient on the list. Then, marketers can deliver the kind of content their subscribers want.

How does Mail Privacy Protection impact tracking pixels?

Mail Privacy Protection is a new feature introduced by Apple in iOS 15, iPadOS 15, and macOS Monterey. This feature pre-loads email images, causing the tracking pixel to fire before an actual recipient opens the message. As a result, email open rates and some other metrics may become inflated and inaccurate.

The Mail Privacy Protection (MPP) feature also hides the IP address of the user, making it more difficult for email marketers to track the location of the user. This means that email marketers may need to rely on other methods, such as geolocation based on the user's email provider, to get a rough idea of the user's location. Of course, you can always ask subscribers where they're located - either in a sign up form, a survey, or in their account profile.

A workaround for Apple's MPP is to segment subscribers who are using this feature. To do that, you need to know who has MPP turned on. Sinch Email on Acid gives users visibility into subscribers email client preferences. So, you can see which subscribers use MPP. When you can segment recipients using MPP, you can more accurately measure things such as subject line split testing, which relies on knowing if messages are getting opened or not.

Tracking pixels and GDPR compliance

In recent years, there's been growing concern and awareness among consumers about how they are tracked and how their data is used. That's led to legislation and regulations that email marketers and others must follow

Most notably, the General Data Protection Regulation (GDPR) is a set of regulations that aim to protect the privacy of European Union (EU) citizens. If your email marketing campaign targets EU citizens, or if anyone from the EU is on your mailing list, you need to ensure that you are GDPR compliant.

One of the key requirements of GDPR is that you need to obtain the consent of the recipient before you can track their activity using tracking pixels. You need to clearly inform the recipient about the use of tracking pixels and give them the option to opt-out if they do not want their activity to be tracked. This is typically done on the privacy policy posted on your website. You should be linking to your company's privacy policy anywhere that you are collecting email addresses.

Get more advice in our collection of GDPR resources for email marketers.

Where to place tracking pixels in email code

Many email service providers offer email marketing analytics and metrics as part of their email solutions. If this is the case, they’ve likely already embedded a tracking pixel into your email campaigns. But let’s say you need to insert an email tracking pixel into your email.

To ensure that tracking pixels work properly, it is important to place them correctly in your email code. Tracking pixels should be placed in the HTML of your email, preferably at the bottom of the email body. This ensures that the tracking pixel is loaded after the rest of the email has been displayed, giving you an accurate measure of the email's open rate.

However, if your email weight is greater than 102kb, Gmail clipping may occur. In that case, your tracking pixel may not fire because it wasn't loaded, and that means it won't track anything. For this reason, some developers place tracking pixels closer to the top near header of the email content.

Remember to minify your email code before sending, and check out an episode of Notes from the Dev: Video Edition in which we explain what can cause this Gmail clipping problem.

What happens when tracking pixels break?

Tracking pixels rely on the recipient's email client to load the image from the remote server. However, there are several reasons why a tracking pixel may not load properly, such as:

• The email client has blocked images from loading
• The email client is not connected to the internet
• The remote server hosting the tracking pixel is down

When a tracking pixel breaks, it may result in inaccurate data being collected. For example, if the tracking pixel does not load, the email may be marked as unopened even if the recipient has actually opened the email. To avoid inaccurate data, you've got to monitor your tracking pixels regularly and ensure that they are working properly.

The bottom line on email tracking pixels

Tracking pixels are an essential tool for email marketers and developers looking to measure the performance of their email campaigns. By tracking open rates, click-through rates, and other metrics, email marketers can optimize their campaigns and improve engagement with their audience.

However, tracking pixels are not without their challenges. The introduction of Mail Privacy Protection by Apple has made it more difficult for email marketers to track the activity of their users. GDPR compliance also requires email marketers to obtain the consent of the recipient before tracking their activity.