How To Use Subdomains To Improve Deliverability, Lead To Better Inbox Placement And Drive Conversions

The number one goal as an email marketer is to get your emails in front of your customers and ultimately drive to a sale. But that’s impossible to do without a strong sender reputation. What’s the point of designing beautiful emails if no one’s even seeing them right? The best way to make sure your emails are always landing in your customers’ inbox and consistently driving conversions is by using subdomains.

Let’s dive in.

Quick refresher: What is a subdomain?

A subdomain is the unique identifier of a specific website, and can be the reason you either land in your customers’ primary inbox or their spam folder. In the below example, ‘’ is referred to as the parent domain, and ‘mail’ as the child domain.

It’s the prefix to the domain that indicates it’s a subsection of the larger domain, and comes immediately after the @ symbol. The great thing about subdomains is that you can put anything before the @ symbol from to

What is deliverability?

The easiest explanation is that deliverability is your ISP sender reputation that’s based on your email engagement. ISPs use this to determine if you’re a trustworthy sender and whether or not you deserve to be placed in the primary inbox, the other inbox, or the dreaded spam folder. Building a strong sender reputation to improve your deliverability doesn’t have to be complicated! The ideal sender is sending a consistent volume of targeted emails that get high engagement on a frequent basis.

How can subdomains improve my deliverability?

Your subdomain is directly tied to your deliverability, and protects your sender reputation long term. Without one your emails are more likely to end up in spam. But that’s not all! If you keep using a parent domain to send all of your emails that get low engagement, ISPs are more likely to determine that you’re not a trusted sender and not worth inbox placement. By not using a subdomain, you’re jeopardizing your parent domain’s sender reputation and possibly hurting the effectiveness of all your future email campaigns. That means customers won’t be receiving your sale promotions, new product release emails, or account support emails. It’s way easier to stay out of your ISPs bad side by using smart deliverability strategies like subdomains, then getting back on their good side once they’ve already decided you’re untrustworthy.

There are naturally some emails that get higher engagement because they’re important for your customer to see. Think account support or transactional emails. By sending those emails from the same domain as your marketing which typically gets lower engagement, you're jeopardizing your chances of those emails being seen by customers. Over time, you might even find that those emails end up in the spam folder. Imagine a customer forgets their password and needs a password reset email. If you’re sending that email from the same domain as your marketing emails which on average get lower engagement, your account support email might also miss their inbox because of poor deliverability. It’s a never ending cycle and not only will it ruin your sender reputation further, but it will likely lead to frustration for your customers, and a negative brand experience.

Wrap up

Even the best designed emails won’t drive conversion, without a strong sender reputation and deliverability. You need to make sure you’re building that trust with ISPs right from the start of your email journey. Making sure you’re using the right deliverability strategies is the key to driving revenue with your email strategy. Email subdomains are the best way to ensure your emails land in your subscribers’ inboxes.