Do you want all of your emails 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 your email deliverability. We’ve got you covered so keep reading to find out whether using subdomains to send email is hurting or boosting your deliverability rates.

Domains Anatomy 101

It’s only right that we begin the discussion at the top level of the URLhierarchy 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. Examples of some of the popular TLDs include: .com, .org, .net, .gov, and .edu.
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 domain 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 a website, “app” is used for a web application, and “m” for a mobile version of a website or an app.

Domain Anatomy 101: Subdomain.SLD.TLD

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 as the company’s website and is considered to be the “root” domain. An email subdomain is a derivative of that “root” domain.

Why should you use an email subdomain?

The answer comes down to two words: ‘email reputation’. Email reputation is what Internet and email service providers use to separate spammers from legitimate email senders. Possessing a good reputation is essential  for successful email deliverability. The domain you’re sending your emails from is directly linked to your email sending reputation, and given that your domain name is used to send your emails is usually your company’s URL or domain, your sending reputation will evidently affect your company.

Domains and subdomains have a different reputation, making it unlikely for one to affect the other. That, in itself, is exactly the reason why you should be using subdomains to send different types of emails within your business. For example: Marketing and sales are two separate departments and therefore employ different email strategies. You wouldn’t want your email marketing campaigns, which are sent in bulk, to influence your sales team’s email deliverability. You should also separate marketing email from transactional email, once again to make sure that transactional email (receipts, welcome email, forgot password, etc) aren’t affected by email recipients who forgot they subscribed to your marketing email.

It’s not too late to start using subdomains and avoid making those mistakes.

What subdomains should I use when sending email?

You can let your creativity run wild, but the important thing is to make sure recipients aren’t confused by it and that they understand that the email is legit. Some good examples:

  • - 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 subdomain.

Wrapping up

Now that we’ve covered what email subdomains are, why you should use them, and how to set them up for sending email using Mailer To Go, you’re all set to send emails 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!