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Everything Marketing Managers Need To Know About Email Subdomains


“Don’t put all of your eggs in one basket.”

That’s the phrase that comes to mind when I think about email subdomains. From the outside looking in, it’s easy to lump all of your email efforts under a single category. They’re all one email program! The reality is that you and your company have different email initiatives all running in tandem. It’s a whole lotta eggs, if you will.

If you want to protect your ever-important deliverability, you should consider using email subdomains.

Have questions? Keep reading to learn more about:

What are email subdomains?

Every email comes from a domain, or web address, shown after the @ symbol in the address. Often, the sending domain will be the same as the company’s website. This is the “root” or main domain.

An email subdomain delivers email from an address underneath the umbrella of your root domain. The subdomain is related to your root domain, but inbox and internet service providers (ISPs) treat it separately.

email subdomain example

You’ve likely seen subdomains used for websites. For example, a subdomain would look like “” instead of on a page on the root domain with “”

Have email subdomain questions? We’ve got answers.

Whether you have a few straggling unanswered questions about email subdomains or need the full rundown, we’ve got you covered.

Why would I even consider separate subdomains?

Email domains (and, by extension, your subdomain) are vital because they play a part in your sender reputation. Since the domain is one of the indicators of where a message is coming from, ISPs use it to keep tabs on your sending activity. As a result, your domain reputation impacts your email deliverability.

Your sender reputation is already a bit of a black box since ISPs don’t tell us exactly how they make decisions about whether or not you’re a trustworthy sender. So, the more you can isolate variables, the better. That’s where email subdomains come into play.

You should consider using separate email subdomains within your email program to track and manage reputation without different activities affecting one another.

If something happens with your root or subdomain, such as a rise in spam complaints or a big swing in send volume that lands you on a blocklist, they’re less likely to affect each other if they’re separate.

You wouldn’t want email marketing slip-ups to impact the reputation of your root domain, which could harm deliverability for sales, PR, or other team members sending personal or outreach emails from the root domain in their own inbox. Or vice versa.


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When should you use an email subdomain?

If emails have different goals or audiences, it might be worth sending them from different subdomains. Here are a few examples:

Transactional emails
Password reset messages and other transactional emails have a higher engagement rate than newsletters. Since email deliverability is very important—if not critical—for transactional emails (nobody wants a password reset message hiding in the spam folder), it helps to use a subdomain.

Promotional emails
We know you do your best to follow email marketing best practices, but spam complaints can happen. If people dislike your promotional content and stop engaging or mark it as spam, the reputation will affect any other message types on the same domain or subdomain.

Global teams
Decentralized teams may want to use subdomains if their email programs are separate or experience widely different send volumes and engagement rates from each other.

Sales and outreach emails
People who work in sales, outreach, or PR in your company likely send messages from the root domain. It’s useful to separate marketing emails from the root domain, so each team’s work doesn’t impact the other.

Do I need multiple subdomains?

If you want to preserve your root domain and separate email types like promotional vs. transactional, you would have multiple subdomains. If you wish to separate from the root domain, you would have one.

Can I just send messages from different names at the same domain?

Changing the name before the @ in the email address isn’t the same as using a subdomain. For example, and use the same domain. The name before the @ is helpful for humans, but reputation is lumped together in the eyes of ISPs.

Some brands, like Amazon, go this route:


If you want to compartmentalize sending to protect deliverability, though, this tactic won’t work. Changing the name before the @ helps you organize senders, but since it isn’t actually a separate subdomain, sending activity from each person impacts the rest.

Should I send from different domains entirely?

Technically, sending different types of emails from separate domains would isolate reputation and deliverability. The algorithms behind ISPs would happily rate your domains as separate entities.

Sending emails from entirely different domains isn’t very people-friendly, though.

As a Litmus community post pointed out, the further you stray from the domain people expect to see in their inbox, the fishier it seems. If you signed up to get deals from, a message from could seem like a scam.

How should I name subdomains?

You have total creative freedom to name your email subdomains however you like. It’s a good idea to choose something that makes sense for your company and subdomain purpose, but ISPs won’t dock you for picking, either.

All email subdomain sending addresses follow the same structure, and it’s up to you to decide how many subdomains you’ll use and what to name them.

The bit that differentiates a subdomain comes after the @ and before your root domain. A period separates the subdomain from the root domain.

Let’s break it down for you again real quick:

email subdomain example

At Litmus, we use because it’s short and memorable. The subdomain “e” denotes “emails” and doesn’t overwhelm our brand name.

At a loss for inspiration? Here’s how other brands name their email subdomains:





Credit Karma


Southwest Airlines


Taco Bell


Paula’s Choice


How do I set up a subdomain?

The exact steps to set up a new email subdomain will vary slightly between email service providers (ESPs), so check with your account manager, customer support team, or the platform’s help docs to get started.

There are best practices that everyone needs to keep in mind, though.

  1. Set up email authentication protocols for the new subdomain.
  2. New subdomains need to be warmed up just like a new IP because inbox providers will see the subdomain as an unknown sender.
  3. Send links in your email to your root domain.
  4. Create rules for subdomain email addresses so any replies go to a monitored inbox.
  5. Redirect subdomains to your root domain in case someone types it in their web browser.

Domain reputation is one part of your deliverability puzzle

Consciously crafting your email subdomain strategy helps you monitor your sender reputation and contain any problems that arise. Your domain reputation is only one factor that impacts your deliverability, though, so your work doesn’t stop there.

It’s best to use both pre and post-send efforts to ensure your messages stay out of the spam folder. Learn more about keeping your deliverability in tip-top shape here.

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Steph Knapp

Steph Knapp

Steph Knapp is a Freelance Content Writer for SaaS and B2B companies