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  3. How do I track which email addresses have opened my emails?

How do I track which email addresses have opened my emails?

Out of the box, there is no way tracking pixels know to which e-mail addresses they have been sent to. Luckily, we do have a solution for this problem. By embedding custom data to your tracking pixels, you can find out which e-mail address has triggered the tracking pixel.

The goal is to send the same tracking pixel to different recipients but have each tracking pixel contain different custom data with the email address of the recipient as the value. You can do this either manually or have this done automatically with your email program.

Tip: If you have privacy concerns about embedding the recipients email address in the tracking pixels, you can also replace the email addresses for user IDs that you personally use (within your business or system). That way, you don't need to have the actual email addresses embedded, but you'll still be able to know which email address connects to which ID.

Say you have an email that you want to send out to four people, and you want to know which of them has opened your email. What you first do is generate a new tracking pixel as usual, for example: Then, for each of the recipients, you add their email address as custom data, such that you end up with four tracking pixels:


As you see, each of the tracking pixel URLs contains the e-mail address of the recipient. So, you can now send four separate e-mails, with the correct tracking pixel URL to its matching recipient.

After the recipients have triggered the tracking pixels, they will show up in the "Custom data" panel on your mail tracking page. Depending on you view type, donut or table, it will show up like this:

Tracked email addresses in the custom data donut chart Tracked email addresses in the custom data table

The tracked email addresses will also show up in the CSV-exports file of both your tracking pixel as tracking URLs:

CSV-export of tracking pixel data with email addresses CSV-export of tracking URLs data with email addresses


If you integrate PastePixel into your own systems, with the use of our API, you can automate this process. But you can also automate this with certain email programs. Some email composing programs, or services, have a feature what is known as merge tags.

With merge tags you can automatically insert data associated to recipients in emails. For example, you can compose your email with "Hello {{firstName}}". Then, when you send your email, the tag {{firstName}} will be replaced with the first name of the recipients. This can also be used with tracking pixels and tracking URLs. For example, you can then insert your tracking pixel as follows: <img src="{{emailAddress}}" alt="" width="1" height="1"/>. How to do this in your case, is depending on the email program or service that you use.