When sending email, a sender’s sending domain is much more than just the naming convention of their brand that ties their email content and web address together in a uniform experience.
An email sending domain is a brand’s “calling card” or unique identifier that allows a sender to be recognized by both an email recipient and the mailbox providers (e.g., Gmail, Yahoo, Outlook, etc.).
A sending domain is a critical part of a sender’s email infrastructure, as it carries an immense amount of legitimacy and “reputation” to both the recipient navigating through their customer journey as well as the mailbox providers who are out to protect their users.
This concept of sending domains should be cared for and protected by those who use them to communicate with their customers.
You now may be thinking, “Ok, yes, I get it. A company’s domain is important, and it should be cared for and protected. Now then, tell me how I do that.”
In comes the concept of subdomains to the rescue!
Subdomains at Your Service
With protection in mind around a sending domain, one should first focus on optimizing who they send to, how much they send to them, and what they send to their recipients.
However, we all know in the email deliverability community that not all email is treated equally, and deliverability challenges (Hello, Microsoft domains! Yes, I am looking at you!) can happen to even the most buttoned-up senders.
The use of a subdomain or a prefix to a branded root domain is a great way to silo off reputation away from a core branded root domain. There are a myriad of reasons why the use of a subdomain is a great idea for siloing email domain reputation. However, two primary reasons are conservation and compartmentalization. Let’s dive into those two areas.
1. Conservation
First, let’s talk about conserving the “image” or “reputation” of a brand, taking a generic example of “abccompany.com.”
ABC Company uses its branded root domain of abccompany.com for internal one-to-one communications as well as mission-critical communications and alerting, among other outreach communications. This company knows that its brand name needs no blemish.
At the same time, ABC Company also knows that its external recipients—aka its customers—may not find this brand as “mission-critical” to their daily lives as the internal folks do within the company. That is why ABC Company uses a subdomain or a prefix to its branded domain of “m.abccompany.com” for its outbound marketing and promotional mailstreams.
Simply adding the “m” subdomain establishes a siloed domain reputation away from the messaging on the root domain. Domain usage is a core contributor to mailbox providers tracking and assessing you as a sender. The assessment of the use of these domains is a key input to a brand’s overall sending reputation.
If ABC Company were to use just “abccompany.com” as the sole domain for their internal company communications, external marketing communications, and external transactional communications, the reputation of this root domain—the lifeblood of the brand—could be negatively affected to where mission-critical transactional messages or internal communications could miss the inbox, if the promotional streams are bringing the root domain reputation down.
The use of “m.abccompany.com” will allow the root domain of “abccompany.com” to be largely protected if “m.abccompany.com” begins to see a decline in domain reputation due to various negative signals (spam complaints, spam traps, non-engagement, etc.) being sent to the mailbox providers.
A natural follow-up question might be, “What if I just create another variance of our root domain versus adding a prefix to our existing domain?” It’s a great question and one we should take seriously. Creating another lookalike domain, like “abccompanyemail.com” to send promotional emails, while keeping “abccompany.com” for the other, more mission-critical outreach emails, creates what we call in the industry “cousin domains.”
Cousin domains or lookalike domains are what many spammers or phishers use to fool a recipient into thinking they are receiving an actual email from that company or brand, even though that company does not own the lookalike email domain.
Yes, this can technically silo out domain reputation, but it looks suspicious to the recipient, and if done enough, mailbox providers can catch on as well. Your best bet as an email sender is to create unique subdomains in front of your own owned root domain for segmented domain reputation.
2. Compartmentalization
Let’s now dive into the aspect of domain compartmentalization and its importance. Going back to the example of ABC Company, chances are that this brand sends out more differentiated commercial mailstreams than just one outbound marketing stream.
If this is a business-to-consumer retail e-commerce brand, it likely sends:
- One-to-many scheduled marketing campaigns
- Triggered one-to-one promotional campaigns based on customer behavior (e.g., abandoned cart emails)
- Mission-critical transactional emails, like receipts or password reset emails
These three mailstreams are distinctly different in who they send to, how often they send to them, and what content is included. ABC Company likely experiences various types of email engagement from its recipients, both positive and negative, between each mailstream. Since these mailstreams see different recipient behaviors, they should be compartmentalized into their own silos, so as not to impact each other.
ABC Company set up “info.abccompany.com” for its mission-critical transactional stream, “m.abccompany.com” for its scheduled marketing campaigns, and “t.abccompany.com” for its triggered one-to-one promotional messages. Each of these streams is building its own domain reputation.
The beauty in creating subdomains is that you can select what you would like as a sender—you aren’t bound to a preset list. The pro tip is to just make the subdomain make sense to both you and your recipients and avoid spammy terms like “deals” or “free.”
Another pro for compartmentalizing commercial mailstreams is when deliverability issues do surface, the troubleshooting of those issues is much easier to identify and mitigate. A sender isn’t shuffling through many different mailstreams under one common sending domain to find out which mailstream was the culprit of the negative deliverability impacts.
Finally, know that the use of differentiated “Friendly From” in the local portion of a domain (what is used before the @ symbol) does not hold the same domain reputation distinction as using a unique subdomain after the @ symbol.
Messages from info@abccompany.com and messages from updates@abccompany.com, although different in the eyes of their recipients, will still be viewed under the reputational umbrella of “abccompany.com.”
In addition, any new unique subdomain to common root domain combination is viewed as a new element in the eyes of the Gmails and Yahoos of the world. A proper warm-up is strongly recommended, even if these new domain combinations are being used on already warmed IP addresses.
Reach Out to Iterable’s Deliverability Team
In summary, using subdomains is a best practice in the email deliverability space. They provide shielded protection away from the root domain as well as create distinctions between the various differentiated mailstreams that a sender may send to its external recipients.
The use of subdomains can help simplify even the most complex of email programs and speed up the troubleshooting and mitigation of email deliverability issues.
If you’re looking for the right deliverability partner for your email program, contact us to speak to our dedicated Deliverability Services team.
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