Identify which recipients opened your mail

Standard tracking pixels only report anonymous opens. However, by using **Custom Data Tags**, you can identify exactly which email address (or User ID) has triggered an open or click.

How it works

The goal is to append a unique identifier to each tracking pixel URL you send. Once the pixel is opened, that identifier will be logged in your **Custom Data** panel.

For example, instead of sending the default URL to everyone, you send personalized versions:

                    https://justopened.com/pixel/fyDxMMWA.png?cstm_data=customer_441

                    https://justopened.com/pixel/fyDxMMWA.png?cstm_data=customer_892

Pro-Tip: If you use an email service provider (like Mailchimp or HubSpot), you don't need to do this manually. You can use Merge Tags to automate it for thousands of recipients at once.

Using Merge Tags

Most email programs allow you to insert variables that are replaced at the moment of sending. Here is how you would embed a tracking pixel with an automated email tag:

                    <img src="https://justopened.com/pixel/CAMPAIGN_ID.png?cstm_data={{email}}" alt="" width="1" height="1">
                

Common email tags include:

Mailchimp: *|EMAIL|*
HubSpot: {{ contact.email }}
Klaviyo: {{ email }}

Viewing the results

In your campaign's **Analytics** page, scroll down to the **"Custom data"** chart. You will see a breakdown of which specific IDs or email addresses have opened the email, and how many times each.

Ready to start identifying?

Open Dashboard Tagging Guide