What is an email domain?

Email domain

An email domain is the part of an email address that comes after the @ symbol. In sarah@yourcompany.com, the email domain is "yourcompany.com." It tells mail servers where to deliver your message and signals to recipients who's sending it.

Free email services give you generic domains like gmail.com or yahoo.com. Custom email domains let you use your own business name, turning generic addresses into branded ones that reinforce your identity with every send.

Why custom email domains matter for business

The domain in your email address shapes how recipients perceive your message before they even open it. A branded domain like @yourcompany.com immediately signals legitimacy, while a free domain can raise questions about whether you're an established business.

Beyond perception, custom domains give you control. You decide who gets an address, what security protocols to implement, and how to handle email when team members leave. With a free provider, you're subject to their rules and limitations.

For email deliverability, custom domains offer a significant advantage. You build sender reputation on your own domain rather than sharing it with millions of other users. When you authenticate your domain properly, inbox providers can verify your emails are legitimate, reducing the chance they'll land in spam.

How email domains work

When someone sends an email to you@yourcompany.com, their mail server looks up the MX (mail exchanger) records for yourcompany.com. These DNS records point to the servers responsible for receiving email on your domain's behalf.

The receiving server then routes the message to the correct inbox based on the username before the @ symbol. This system allows a single domain to support unlimited email addresses, from info@ and support@ to individual team member addresses.

Your domain's reputation travels with every email you send. Inbox providers track engagement signals, spam complaints, and bounce rates associated with your domain. A strong domain reputation means better inbox placement, while a damaged one can tank deliverability across your entire organization.

Setting up a custom email domain

Getting your own email domain involves three main steps:

1. Register your domain name through a registrar if you don't already own one. Choose something short, memorable, and aligned with your brand.
2. Select an email hosting provider to manage your mailboxes. Options range from Google Workspace and Microsoft 365 to specialized business email services.
3. Configure your DNS records to connect your domain to your email host. This includes MX records for mail routing and authentication records for security.

The technical setup typically takes under an hour. Most email hosts provide step-by-step instructions for adding the required DNS entries.

Email authentication: protecting your domain

Authentication protocols verify that emails claiming to come from your domain actually originate from authorized servers. Without them, anyone can forge your address in the "From" field.

SPF (Sender Policy Framework) lists which servers can send email on your domain's behalf. Receiving servers check incoming mail against this list.

DKIM (DomainKeys Identified Mail) adds a cryptographic signature to your emails. Recipients can verify the signature matches your published public key, confirming the message wasn't altered in transit.

DMARC ties SPF and DKIM together with a policy telling receivers what to do when authentication fails. It also provides reports on who's sending email using your domain.

Implementing all three protocols protects your brand from spoofing and improves deliverability by proving your emails are legitimate.

Ready to send from your own domain? Start your free ActiveCampaign trial and connect your custom email domain in minutes.

Best practices for managing email domains

Keep business and personal separate. Use your custom domain exclusively for professional communication. Mixing purposes muddies your sender reputation and complicates security.

Create role-based addresses strategically. Addresses like info@, support@, and sales@ help route inquiries to the right team, but don't create more than you'll actively monitor.

Monitor your domain health regularly. Track bounce rates, spam complaints, and authentication pass rates. Sudden changes often signal problems that need immediate attention.

Plan for team changes. When employees leave, you control what happens to their email. Forward messages to a colleague, set up an autoresponder, or deactivate the address entirely.

Document your DNS settings. Authentication records can be accidentally deleted during website changes. Keep a record of your SPF, DKIM, and DMARC configurations.

Common email domain mistakes to avoid

Using your ISP's email domain ties your business communication to your internet provider. Switch providers, and you lose your email address along with any reputation you've built.

Choosing an overly long or complex domain creates friction. Every time someone types your address, they risk making errors. Keep it short enough to say aloud without spelling it out.

Skipping authentication leaves your domain vulnerable to spoofing. Attackers can send phishing emails that appear to come from your address, damaging your reputation and potentially harming your customers.

Neglecting email list hygiene hurts your domain reputation over time. High bounce rates and spam complaints signal to inbox providers that your sending practices are questionable.

FAQs

Can I use my website domain for email?
Yes, and you should. Using the same domain for your website and email creates consistency and makes it easy for customers to find you online after receiving your message.

How long does it take for a new email domain to build reputation?
New domains start with neutral reputation. Building positive sender reputation typically takes several weeks of consistent, engaged sending. Start with your most active subscribers and gradually expand.

What happens to my email if I let my domain registration expire?
You lose access to all email on that domain. Worse, someone else could register it and receive messages intended for you. Set your domain to auto-renew and keep payment information current.

Can I have multiple email domains for one business?
Yes, though managing reputation across multiple domains requires more effort. Some businesses use separate domains for transactional and marketing email to isolate reputation risks.

Want to maximize deliverability from your custom domain? Explore ActiveCampaign's email marketing platform and see how authentication, automation, and analytics work together.