Subdomain Emails: Should I Use A Subdomain To Send Email?

Subdomain Emails: Should I Use A Subdomain To Send Email?

Do you want all of your marketing emails, transactional emails, and promotional emails to be delivered successfully to your customers' inboxes?

Are you taking every step necessary to achieve this goal?

Well, what you may not know is that using subdomains to send email has a crucial impact on email deliverability.

Keep reading to find out whether using subdomains to send email is hurting or boosting your deliverability rates.

For our latest guide on the topic, please explore email subdomain 101, or browse our posts on email deliverability best practices, transactional vs. bulk email, and more.

Domain anatomy 101

It's only right that we begin the discussion at the top level of the URL hierarchy and talk about the top level domain or TLD in short.

TLD is the last segment of a domain name, meaning everything that follows the last dot of a domain name. Some of the popular top-level domains include: .edu, .com, .net, .org, .gov, etc.

The next level in the URL hierarchy is the SLD, which stands for second-level domain (makes sense, right?). The SLD is located right before the TLD and, together with the TLD, identifies the domain name.

Now that we have that settled, it's time to tackle the third level of the domain hierarchy and the reason we are all gathered here today, the subdomain.

A subdomain shows up before the SLD and accompanies the beginning of a website's parent domain name name. This added factor helps to organize and navigate the inner workings of a website, by dividing content into specific sections.

For instance “www” is usually used for the main domain of a website, “app” is used for a web application, and “m” for a mobile version of a website or an app.

domain anatomy 101 diagram

Domain names are used everywhere on the internet:  when browsing websites, uploading files to SFTP servers, and when sending and receiving email. In the context of the email dialogue, every email is sent from an address at a certain domain that appears after the @ symbol (e.g.

This domain will commonly be the same domain as the company's website and is considered to be the “root” domain. An email subdomain is a derivative of that “root” domain.

For a quick video intro on the topic, watch the following video by "For the Love of Emails" on YouTube.

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Why should you use an email subdomain?

The answer comes down to two words: email reputation. Email sender reputation is what Internet service providers and email service providers use to separate spammers from legitimate email senders. Possessing a good reputation is essential for successful email campaigns and staying far outside of the dreaded spam folder.

The domain you're sending your emails from is directly linked to your email sender reputation, and given that the domain name used to send your emails is usually your company's URL or domain name, and a poor sender reputation will have negative consequences.

Domains and subdomains have a different reputation, making it unlikely for one to affect the other. Therefore, it is industry best practice to use separate subdomains to send different types of emails within your business.

For example: your marketing team, sales team, and support teams are all separate departments and therefore employ different email strategies. The marketing team sends marketing messages, promotional emails, and standard marketing communication. The support team sends transactional emails, such as receipts, welcome emails, password resets, order confirmations, etc.

You wouldn't want your email marketing campaigns, which are sent in bulk, to influence your support team's email deliverability. Using separate email subdomains is in fact a great email strategy to ensure that transactional emails aren't affected by email recipients who may have unsubscribed to your marketing email.

It's not too late to start implementing email subdomain best practices to avoid making those mistakes.

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What subdomains should I use when sending email?

You can let your creativity run wild, but the important thing is to make sure recipients who see the messages aren't confused by it and that they understand that the email is legit.

Some good examples of multiple subdomains to send messages are as follows:

  • - send receipts and invoices from this subdomain

  • - send your marketing email and newsletters from this subdomain

  • - send personal email from this subdomain

How do you use subdomains with Mailer To Go?

To add a domain to Mailer To Go, simply follow these steps:

  1. Click “Add domain”

  2. Enter your domain name and select the region to send email from.

  3. Copy the DKIM records to your domain's DNS records in order to add DKIM email authentication and verify your domain.

Once you add a domain to Mailer To Go, you can use any email address within this domain or within any email subdomain example above (i.e. a subdomain email address).

In closing

We've covered what email subdomains are, why you should use subdomain email addresses, how they boost domain reputation, and how to set them up for sending email using Mailer To Go.

So, you should be all set to send emails from a subdomain email address with confidence.

If you have any questions regarding this topic or how to get started, please reach out to us via chat and we will be happy to guide you and provide more information! Thanks so much for reading!

Explore our latest posts for reviews of SendGrid alternatives and the best email providers of 2023.

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Frequently asked questions

What is a subdomain in emails?

A subdomain in emails is an additional component of your root domain that is added as a prefix to your main domain. For instance, if your main domain is, a subdomain could be

Emails can be sent from the subdomain instead of the root domain, which can help manage the reputation of your email sends and improve deliverability.

Why should I use a subdomain for emails?

Using a subdomain for emails can help you maintain and manage your email reputation separately from your main domain. This is particularly useful if you send different types of emails (e.g., transactional emails, marketing emails) and want to manage their reputations separately.

It can also improve email deliverability and help ensure your emails land in your subscribers' inboxes.

How do I set up a subdomain for emails?

Setting up a subdomain for emails typically involves creating the subdomain through your domain provider and then configuring your email service provider to send emails from this subdomain.

For instance, with Mailer To Go, you can easily set up a subdomain for your emails and start sending transactional emails from this subdomain.

Can a subdomain affect my email deliverability?

Yes, a subdomain can affect your email deliverability. Each subdomain may have its own reputation rate that does not impact others or the root domain.

This means that if you send a lot of emails from a subdomain and these emails have a high bounce rate or are often marked as spam, this could negatively affect the reputation of the subdomain and thus your email deliverability.

Can I use multiple subdomains for emails?

Yes, you can use multiple subdomains for emails. This can be useful if you want to separate different types of email sends (e.g., transactional emails, marketing emails) or if you want to separate emails sent to different segments of your audience.

Each subdomain will have its own separate reputation, so it's important to manage each one carefully to ensure good email deliverability.

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