Using one or more dedicated subdomains for bulk email, such as newsletters, marketing campaigns, and automated messages, is a widely accepted best practice in email marketing.

The main reason is to separate bulk email traffic from regular, direct communication (one-to-one emails) sent by employees or organizations using their primary domain.

Benefits of Using a Separate Subdomain

  • Separation of email traffic: Bulk emails are kept separate from regular business communication, such as personal emails exchanged between employees, customers, and business contacts.

  • Protection of domain reputation: Bulk email typically involves higher sending volumes and a greater risk of spam complaints and bounces. Using a dedicated subdomain helps limit the potential impact on the deliverability of regular business emails.

  • Separate sending reputation: Subdomains can establish their own sending reputation, allowing different types of email traffic to be managed and monitored more independently.

  • Greater control: Using multiple subdomains makes it possible to separate different types of email traffic, such as marketing campaigns and transactional emails.

Practical Example

For a primary domain such as company.com, the following setup could be used:

  • company.com for regular, personal business emails (one-to-one communication).

  • newsletter.company.com for newsletters and marketing campaigns.

  • transactional.company.com for automated transactional messages.

Best Practice

Use at least one dedicated subdomain for bulk email to keep this traffic separate from regular business email communication. When sending different types of emails, using multiple subdomains may be beneficial.

A subdomain does not provide complete reputation isolation. Mailbox providers may also consider the reputation of the primary domain. Proper configuration of SPF, DKIM, and DMARC, along with following good email sending practices, therefore remains essential.