Set Up a Custom Tracking Subdomain (URL)

Article author
Sarah Malone


A tracking domain is a secondary (or sub) domain name related to your original domain. It allows Apollo to redirect a tracking pixel added to emails to track opens, clicks, and unsubscribes.

Tracking pixels are often flagged as spam. Set up a custom tracking subdomain to improve the delivery rates for the emails you send through Apollo.

Bonus Resources

Custom tracking subdomains is only one part of the equation. To make it into your contact's inbox consistently, take a look at these email deliverability best practices. Also, stay within recommended sending limits and download this checklist anytime you need a cheat sheet.

Refer to the sections below to create, connect, and manage a new tracking subdomain.

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Create a Custom Tracking Subdomain

To create a custom tracking subdomain, you need to first create a CNAME record. To do so, you need admin access to your domain management account.

Domain Management Interface

Please note, every domain provider has a different domain management interface. If you need help creating a CNAME record, visit the online knowledge base for your domain provider and search for "create CNAME".

The table below provides more details about the type of information you will need.

Field Definition Field Information Additional Notes
DNS Record Type DNS Records include essential information about your domain or host. To set up a tracking subdomain, you need to select the record type: Canonical Name (CNAME). CNAME A CNAME record maps an alias name to a canonical domain name.
Host/Host Name/Name Choose any name that is not directly related to your website. This name will become the subdomain in the URL that you create: subdomainexample
  • Do not include spaces.
  • This must be text only.
  • Do not include periods.
  • Do not include any words that SPAM filters can easily identify, such as tracking.
Value/Data/Points To The value you enter establishes the connection between your subdomain and the Apollo tracking servers. This field must be
TTL TTL is a technical term that refers to how often your subdomain information will be rechecked by relevant servers. Leave as Default You can leave this field as whatever value your domain provider uses by default.

As an example, here's the layout from an Amazon Web Services (AWS) account, one of the most popular providers. You will need to add data into all of the same CNAME record fields. Once you create and save your CNAME record, it can take between 2-24 hours to fully propagate.

Create CNAME example

Fields May Vary

If you're using other providers like GoDaddy or Cpanel, reference their documentation on subdomains to ensure you're reviewing the most up-to-date information specific to your use case.

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Connect a Custom Subdomain to Apollo

To connect a custom subdomain to Apollo:

  1. Launch Apollo, click the settings icon in the navbar, and then click Tracking Subdomains. Tracking Subdomains
  2. Click New Subdomain. Add New Subdomain
  3. Enter the custom subdomain in the Domain text-box. Subdomain Search Bar
  4. Click Create. Create Subdomain
Default Subdomain

Please note, you can only use 1 tracking subdomain at a time. If you connect several tracking subdomains, Apollo will only use the one you set as default.

When you connect your CNAME record, the word healthy appears on the right-hand side of your screen.

Healthy Icon

You have now connected your custom tracking subdomain. As a best practice, please check your subdomain settings 24 hours after you finish the setup steps to ensure a healthy connection.

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Troubleshooting Errors

If you receive an error message or see the word Unhealthy on the right of your tracking subdomain after you connect it with Apollo, there are 2 main causes:

  1. CAA permission error
  2. CNAME error

Refer to the following information to help troubleshoot the issue.

CAA permission error

Apollo uses Let's Encrypt for tracking domains. If your team has set up a CAA record and you have not listed Let's Encrypt, please contact your DNS admin to update your CAA settings.

When you have given Let's Encrypt permission to generate certs, follow the steps in this article to reconnect your domain with Apollo.

CNAME error

There are several potential causes for CNAME errors. To fix the issue:

  • Check for spelling mistakes
  • Confirm that you filled in all the required fields in your domain management account
  • If you've only just created a CNAME record, wait 24 hours. Then, try connecting your custom subdomain to Apollo again
  • If the problem persists, contact your domain provider's support team. Your account may have been deleted or deactivated on their end
Speak to Support

If you're still having issues connecting a custom subdomain to Apollo, we're only a message away! Reach out to Apollo support for more help.

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Manage Tracking Subdomains in Apollo

Refer to the section below for more information about how to make a tracking subdomain the default domain, check the statistics, and deactivate a subdomain.

Make a Tracking Subdomain Default in Apollo

You can only use one tracking subdomain at a time. The tracking subdomain you set as default is the one that Apollo will use.

To set a tracking subdomain as default, click the additional options (...) button on the right-hand side of the tracking subdomain. Then, click Make Default.

Make Default

You have now changed the default tracking subdomain.

View Tracking Statistics

To evaluate the performance of the emails you send and keep track of the open, click, and unsubscribe rates, you can access the Apollo tracking statistics.

To view tracking statistics, click the additional options (...) button on the right-hand side of the tracking subdomain. Then, click Check Stats.

Check Stats

The Stats modal includes key statistics related to the performance of the emails sent with the default tracking subdomain.

Stats Modal

Apollo Tracking Stats

Please note, few contacts open an email immediately after you send it. For this reason, Apollo tracking stats reflect data from the previous week and month rather than from the current week and month.

Deactivate a Tracking Subdomain

Tracking Subdomain Status

If your tracking subdomain is Healthy, your recipients’ email servers are not flagging your emails as spam. When you check your email statistics in Apollo, you should see high open rates and low bounce rates. If your tracking subdomain is Unhealthy, your recipients’ email servers are flagging your emails as spam.

You can expect that email servers will still occasionally flag your emails as spam. If you start to see a dramatic decrease in your open rates or an increase in spam-blocked emails, you can follow the instructions in the Create a Custom Tracking Subdomain section to create a new tracking subdomain. Then deactivate the current tracking subdomain to remove it from your options and reset your deliverability. Also, remember to follow email deliverability best practices to avoid that pesky spam filter.

To deactivate a tracking subdomain, click the additional options (...) button on the right-hand side of the tracking subdomain. Then, click Deactivate.

Deactivate Subdomain

You have now deactivated the tracking subdomain.

Tracking Links Do Not Expire

Please note, tracking links that utilize your custom tracking subdomain do not expire unless you delete the domain.

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