Permissions & Deliverability

Why Your Sender Email Address Matters in Email Marketing: When It’s Best to use a Subdomain

Robert BrandlCharlotte Evans

By Robert & Charlotte

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sender email address

So you’ve chosen your email marketing service and are ready to write your first newsletter? How exciting!

But now you need to decide on a sender email address. While it seems trivial, it’s actually an important piece of the email delivery puzzle. When set up correctly, it creates trust among your readers and ensures your newsletters are delivered.

But what are the current best practices around the sender email address? I'll explain what you need to watch out for. Let's start with general best practices and then move on to more specific tips depending on the types of emails you are sending (bulk vs. transactional messages).

We'll also investigate when it's best to use a subdomain vs your main domain for your sender email address.

General Best Practices for Your Sender Email Address

Maintain Consistency: Avoid any confusion for your audience by sticking to a consistent sender name and address. This helps maintain a strong sender reputation and helps to prevent your emails from landing in the junk email box. The Republican party doesn't follow this best practice, and it's costing them. Find out more in our political email study.

Email Authentication: This isn't just tech jargon. SPF, DKIM, and DMARC are your safeguards. They tell email servers that your emails are legit and protect your subscribers from potential phishing threats using your name. We know it sounds complicated, but luckily for you, we’ve created a guide to help you learn how to properly authenticate your emails.

Avoid “No-reply” Addresses: Everyone's experienced the impersonality of a ‘no-reply' address. Instead, we recommend warming up your engagement by allowing subscribers to respond to your emails. It makes your brand approachable and can provide valuable feedback. If you really can’t reply, consider setting up an autoresponder message, directing your readers to your contact form.

Monitor “Reply-to” Addresses: If you encourage replies, be prepared to engage. Whether it's feedback, queries, or issues, having someone on standby to respond helps to portray a positive brand image.

Avoid Free Email Providers: Using generic email providers like Gmail, Yahoo, or Outlook can negatively impact your deliverability. Many email providers flag newsletters from these addresses as spam, especially when you use such a sender address for your bulk emails.

These recommendations are generally valid regardless of the types of emails you're sending. Now, let’s delve into specifics for newsletters and transactional email messages.
deliverability checklist magnet

Best Practices for Newsletters and Other Mass Emails

An obvious email address for your company’s newsletter might be, your company’s main domain. And while there is nothing inherently wrong about it, let’s compare it to setting up a subdomain for your sender address (e.g.

Pros and Cons of Using a Subdomain for Your Newsletter’s Sender Email Address:


  • Authentication: You can easily set up specific email authentication methods (like SPF, DKIM, and DMARC) for the subdomain without affecting your main domain's settings. This is especially important if you are using a range of different email service providers (e.g. Mailchimp) as well as company email services (e.g. Google Workspace). Each of these services requires its own SPF record, however, due to the limitations of this protocol, you usually can’t add more than 5 different email services. However, by using a subdomain, like for instance, you can configure it specifically for newsletters, whereas your main or root domain will send regular emails.
  • Sender Reputation: Let's imagine the unlikely event of you running into delivery issues because of increased spam reports for your newsletters. This could affect the deliverability of the regular company emails that your employees use. Using a subdomain can protect you from that.
  • Malicious signups: SaaS (Software as a Service) companies are particularly vulnerable to attracting spammers. If spammers find a security hole that allows them to send spam using your email address (e.g. through a web form), using a subdomain will protect your regular company emails.


  • Recognition: Some users might be confused or suspicious of a subdomain, especially if they're used to seeing your primary domain. It doesn’t help that spammers often use domain names that are very similar to company’s real domains. For example, a spammer could easily register something like, which could be confused with
  • Setup: Requires a bit more technical setup and technical overhead than using your primary domain. But overall, this isn’t a strong factor.

netflix sender email

Newsletter from Netflix using a subdomain sender address (for bringing bad news)

The vast majority of larger organizations all use subdomains to send their newsletters. Examples include: Netflix, HBO, Amazon, Shopify, Wix, Squarespace, Coldplay (the band), Wise, BBVA, and Santander (international banks).

mailerlite sender email

Newsletter from MailerLite sent from their main domain

Interestingly, looking at email service providers themselves, we found that ActiveCampaign, Mailchimp, Moosend, MailerLite, and AWeber all send their newsletters from their main domains. Typically, they opt for email addresses such as “newsletter@”, but some of them even use generic help@ or info@ email addresses, which I find particularly interesting.

Why, you ask?

Because info@ is an email address that is commonly used for general inquiries to the company. Sending out a mass email from this address without specifying a different reply-to address, means, that all out-of-office emails and other junk (if you've ever sent a large newsletter you will know what I am talking about) will land in this very inbox. I can only hope they have robust filtering mechanisms in place 🙏

My best guess for why they prefer using the root domain is branding and trustworthiness. Also, as an email service provider, it’s unlikely that they will use many different newsletter services (which simplifies the authentication part).

Hence, as the number of email and newsletter services used increases within your organization, the more likely it is that sending via a subdomain makes more sense.

Of course, you can also start out on your root domain and change later on if necessary. But do keep in mind that you will lose much of the trust associated with your old sender email address by switching to a different domain.

Best Practices for More Personal Messages (e.g. autoresponders and transactional emails)

Looking at messages that are being sent on a more personal level, such as transactional messages and also “semi-personal” messages like autoresponders, sending from the root or main domain becomes more common. Brands such as Amazon, Spotify or Namecheap follow this approach. Yet, my observation is that subdomains are still more popular with larger senders.

It's important for you to note that if your goal is to receive an actual response from an email, be it an autoresponder or a drip email campaign, you should absolutely use your root domain as the sender email address. Otherwise, many people might be hesitant to reply, thinking it isn't a genuine email address.


Deciding on the right sender email address might seem like a small detail, but, as we've seen, it's anything but.

Whether you go for the main domain, opt for a subdomain, or mix it up based on the type of email, it's essential to prioritize the trust and recognition of your audience.

Smaller businesses are generally fine using their main domain. That’s also what we do at Tooltester (we’re a business with 10 employees). A more personal touch goes a long way.

For larger organizations, particularly those of medium size and up, I'd generally recommend a subdomain for newsletters. It offers a layer of separation and added flexibility.

However, for transactional emails, which are often more personal in nature, I am more in favor of using the main domain, no matter the company size.

It's all about striking the right balance. At the end of the day, emails are about communication, and your sender address sets the tone even before the content is read.

If you have any further questions or feedback, please leave a comment! We read each one of them.

The authors

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Robert Brandl

Founder and CEO

Hello! I'm Robert, an email marketing expert with over 15 years of experience. After honing my skills at an agency by serving major corporations, I founded EmailTooltester as a passion project to help small and medium-sized businesses. Connect with me on LinkedIn where I regularly share my best email marketing knowledge.

Charlotte Evans

Content Manager

Hey, I'm Charlotte! I've always been enthusiastic about helping others. After working for various tech startups and eCommerce businesses, I developed a strong passion for email marketing. Now, at EmailTooltester, I'm putting this knowledge to good use by recommending the very best digital tools for your business.

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We keep our content up to date

09 Jul 2024 - Small update regarding SaaS companies.

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This article has been written and researched following our EmailTooltester methodology.

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