Summary
The general consensus across marketers, experts, and technical documentation is that utilizing separate subdomains for different email types (transactional, marketing, etc.) is a highly recommended practice for improving email deliverability and managing sender reputation. The primary benefits include isolating reputation damage, improved control over authentication and sending practices, and better alignment with tracking and reporting systems. However, the ultimate decision depends on individual business goals and resources.
Key findings
- Reputation Isolation: Using separate subdomains isolates reputation, so issues with one subdomain will not impact the others.
- Enhanced Deliverability: Segmenting traffic helps protect the primary domain and improve overall deliverability, especially for critical transactional emails.
- Granular Control: Using separate subdomains gives control over authentication (SPF, DKIM, DMARC), IP warming, and sending practices for each email stream.
- Tracking System Alignment: The tracking link strategy should be determined by what best integrates with the existing tracking and reporting system.
Key considerations
- Business Goals: Domain decisions must support broader business objectives, not only technical considerations.
- Authentication Configuration: Proper authentication (SPF, DKIM, DMARC) is essential for each subdomain to maximize deliverability.
- IP Segmentation: Consider using separate IPs for each subdomain to further segment traffic.
- IP Warming: Each dedicated IP used for separate subdomains needs to be properly warmed up.
- Resource Allocation: Managing multiple subdomains requires resources and attention to detail.
What email marketers say
10 marketer opinions
The consensus among email marketers is that using separate subdomains for different types of email (transactional, marketing, etc.) is a beneficial strategy for managing and protecting your email sending reputation. Isolating traffic allows you to contain reputation damage, improves deliverability, and provides granular control over authentication and IP warming.
Key opinions
- Reputation Isolation: Using separate subdomains isolates email sending reputation, so issues with one subdomain don't affect others.
- Improved Deliverability: Segmenting email traffic across different subdomains protects the primary domain and enhances deliverability.
- Granular Control: Separate subdomains give you control over reputation, authentication (SPF, DKIM, DMARC), and IP warming for each stream.
- Risk Mitigation: Segregation minimizes risks and the impact of a poor sending reputation on overall domain health.
- One-to-One Tracking: Using one to one tracking links with corresponding subdomains can protect your sending domains from being taken down.
Key considerations
- IP Warming: If using dedicated IPs, each subdomain needs to be warmed up separately.
- Authentication: Properly configure authentication (SPF, DKIM, DMARC) for each subdomain.
- Dedicated IPs: Consider using different IPs to segment traffic for different subdomains.
Marketer view
Email marketer from SendGrid indicates that warming up dedicated IPs for each subdomain will protect your overall reputation. They suggest keeping everything separate for better control
1 Apr 2023 - SendGrid
Marketer view
Email marketer from Litmus explains that using subdomains for different types of email allows you to isolate your reputation. If one subdomain gets a poor reputation, it won't necessarily affect the others.
28 Jun 2023 - Litmus
What the experts say
4 expert opinions
Experts emphasize that the decision to use separate or global tracking links for different email subdomains depends on several factors. The primary focus should be on building a tracking system that aligns with your reporting needs and business goals. Isolating reputation is a key advantage of separate subdomains, while proper configuration of authentication (SPF, DKIM, DMARC) is essential regardless of the chosen approach.
Key opinions
- Tracking System Alignment: The choice of tracking link strategy should primarily be driven by what best suits your existing tracking and reporting system.
- Reputation Isolation: Separate subdomains can isolate reputation issues, preventing problems with one subdomain from affecting others.
- Limited Damage: A single mistake is unlikely to break all your email sending capabilities.
Key considerations
- Business Goals: Domain decisions should support broader business objectives and not just technical considerations.
- Authentication: Properly configure authentication (SPF, DKIM, DMARC) for each subdomain to maximize deliverability.
- IP Segmentation: Consider using different IPs for different subdomains to further segment traffic.
Expert view
Expert from Word to the Wise emphasizes the importance of properly configuring authentication (SPF, DKIM, DMARC) for each subdomain and using them to isolate different types of email traffic. She also advises using different IPs to segment traffic for different subdomains.
20 Sep 2021 - Word to the Wise
Expert view
Expert from Email Geeks shares that in the current system: one mistake is never going to break all your mail, as that’s just not how the big filters work.
16 Mar 2023 - Email Geeks
What the documentation says
5 technical articles
Technical documentation consistently recommends using subdomains to separate email traffic types (transactional, marketing, etc.) for improved reputation management and deliverability. This segmentation allows for distinct reputations, different authentication methods, and isolated IP configurations.
Key findings
- Reputation Segmentation: Subdomains enable segmentation of email reputation based on sending practices, as evaluated by major providers like Google.
- Traffic Separation: Using subdomains separates different types of email traffic, such as transactional and marketing emails.
- Enhanced Deliverability: Isolating email domains improves deliverability, especially for critical transactional emails.
Key considerations
- Authentication Flexibility: Separating traffic allows you to implement different email authentication methods (SPF, DKIM, DMARC) for each subdomain.
- Dedicated IPs: Using dedicated IPs in conjunction with subdomains provides additional segmentation and control over email sending.
Technical article
Documentation from Google explains that they evaluate reputation on a per-domain and per-IP basis. Using subdomains allows for segmentation of reputation based on sending practices.
23 Jul 2022 - Google
Technical article
Documentation from AWS suggest that dedicated IPs and subdomains allows for segmentation of traffic
14 Jan 2023 - AWS
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