Sending Subdomain Architecture

Learn how to segment your email traffic across multiple subdomains to isolate risk and optimize your sender reputation.

Differentiating Domains & Subdomains

An email subdomain is a prefix added to your main domain name that creates a distinct sending identity.

If your company domain is company.com, you might use subdomains like:

• news.company.com, for your newsletters and marketing communications.

• account.company.com, for your service related communications.

• Etc

Why Use Separate Subdomains Instead of a Root Domain?

Most mailbox providers track the reputation of each subdomain separately. Think of it like having different phone numbers for different departments in your company—each builds its own reputation based on how it's used.

We strongly recommend using dedicated subdomains for different email types—particularly separating transactional emails (e.g. password resets, receipts, account notifications) from marketing emails (e.g. newsletters, promotional campaigns).

Here is how a typical email setup looks like:

Know more on the ideal sending structure and subdomains in our dedicated article: Sending Infrastructure Best Practices