Summary
The overwhelming consensus among marketers, experts, and documented best practices is that separating authentication for transactional and bulk emails is highly recommended to improve deliverability and maintain distinct sender reputations. This separation can be achieved through various methods, including using separate IP addresses, subdomains, sending domains, or DKIM domains. Separating authentication helps prevent deliverability issues with bulk emails from negatively impacting transactional emails, which are crucial for user experience. However, if the existing setup is functioning well, changes may not be necessary. Additionally, verification emails are often targeted for abuse, reinforcing the need for separate authentication. Using separate SPF records also allows for dedicated authentication and avoidance of SPF limitations.
Key findings
- Improved Deliverability: Separating authentication enhances email deliverability by isolating sender reputations.
- Distinct Reputation: Maintaining separate sender reputations for transactional and bulk emails prevents issues in one stream from affecting the other.
- Various Separation Methods: Different methods exist for separating authentication, including separate IPs, subdomains, sending domains, and DKIM domains.
- Verification Abuse Prevention: Separation helps protect transactional emails, particularly verification emails, from abuse and spam filters.
- Separate SPF Records: Having separate SPF records allows for distinct authentication configurations and helps avoid SPF limits.
- Industry Best Practice: Separating transactional and bulk emails is generally considered an industry best practice for maintaining optimal deliverability.
Key considerations
- Current Setup: Assess the performance of the current email setup and consider whether changes are necessary if it's functioning well.
- Technical Expertise: Implementation of separate authentication methods requires technical expertise in DNS records and email authentication protocols (SPF, DKIM, DMARC).
- Resource Allocation: Allocate sufficient resources and expertise to set up and maintain separate email infrastructures.
- Email Volume and Risk: Consider the volume of transactional emails and the potential for abuse when determining the level of separation needed.
- Third-Party Solutions: Consider using third-party email providers for transactional emails to ensure reliable delivery and reputation management.
What email marketers say
12 marketer opinions
The general consensus is that separating authentication for transactional and bulk emails is a best practice to improve deliverability and sender reputation. This can involve using separate IP addresses, subdomains, sending domains, or DKIM domains. It is important to note that if the current setup is working well, it may not be necessary to make changes. Considerations include the volume of emails, potential for abuse, and the existing infrastructure.
Key opinions
- Deliverability Improvement: Separating authentication improves deliverability by isolating the sender's reputation.
- Reputation Management: Distinct sender reputations for transactional and bulk emails prevent issues in one stream from affecting the other.
- Authentication Options: Various methods exist for separation, including separate IPs, subdomains, sending domains, and DKIM domains.
- Verification Abuse: Verification emails are particularly prone to abuse, making separate authentication beneficial.
- SPF Limits: Separate SPF records allows you to have separate authentication and avoid SPF limits.
Key considerations
- Existing Setup: If the current email setup is working without issues, consider whether changes are necessary.
- Email Volume: The volume of transactional emails may influence the necessity of separation.
- Abuse Potential: Assess the risk of abuse for transactional emails, particularly verification emails.
- Infrastructure: Evaluate the existing email infrastructure and the effort required to implement separation.
Marketer view
Email marketer from EmailProviderFeedback shares that it is best practice for authentication to setup your transactional emails with a third party to keep them seperate.
20 May 2025 - EmailProviderFeedback
Marketer view
Email marketer from StackExchange shares that using a separate subdomain for transactional email is best practice for deliverability.
9 May 2024 - StackExchange
What the experts say
2 expert opinions
Experts agree that separating authentication for transactional and bulk emails is a best practice. This approach helps maintain distinct sender reputations for each type of email, preventing issues in one stream from negatively impacting the deliverability of the other. By implementing separate SPF, DKIM, and DMARC configurations, organizations can ensure that their transactional emails are delivered reliably, even if their bulk email campaigns experience deliverability challenges.
Key opinions
- Best Practice: Separating authentication for transactional and bulk emails is considered a best practice.
- Distinct Reputation: Maintaining distinct sender reputations improves deliverability for both email types.
- Prevent Impact: Separation ensures that issues in one email stream do not negatively affect the deliverability of the other.
Key considerations
- Implementation Effort: Implementing separate SPF, DKIM, and DMARC configurations requires technical expertise and effort.
- Monitoring: Ongoing monitoring is necessary to ensure that both email streams maintain their distinct reputations and deliverability.
Expert view
Expert from Word to the Wise emphasizes the importance of sender reputation for different email streams. Separating transactional and marketing emails ensures that issues with one stream do not negatively impact the deliverability of the other.
28 Jul 2023 - Word to the Wise
Expert view
Expert from Spam Resource explains that separating authentication (SPF, DKIM, DMARC) for transactional and bulk emails is a best practice. This helps maintain distinct reputations for each type of email, improving deliverability.
15 May 2025 - Spam Resource
What the documentation says
3 technical articles
Technical documentation consistently recommends separating transactional and bulk emails using distinct domains or subdomains to create separate SPF records and configure authentication protocols (Sender ID, SPF, DKIM, and DMARC) independently. This separation allows for better control over sender reputation and improves email authentication and filtering, ultimately enhancing deliverability for both types of email.
Key findings
- Domain Separation: Using separate domains or subdomains is a key strategy for separating email streams.
- Distinct SPF Records: Separation enables the creation of distinct SPF records for transactional and bulk emails.
- Authentication Configuration: Configuring Sender ID, SPF, DKIM, and DMARC records differently improves authentication and filtering.
- Reputation Control: Separation allows for better control over sender reputation for each email type.
Key considerations
- Technical Expertise: Implementing these configurations requires technical expertise in DNS records and email authentication protocols.
- Infrastructure Changes: Setting up separate domains or subdomains may require changes to the existing email infrastructure.
- Ongoing Maintenance: Regular monitoring and maintenance of DNS records and authentication configurations are necessary to ensure continued deliverability.
Technical article
Documentation from Microsoft explains that configuring Sender ID, SPF, DKIM, and DMARC records differently for transactional and bulk email domains helps improve email authentication and filtering.
14 Feb 2024 - Microsoft
Technical article
Documentation from SparkPost explains that using a separate sending domain for transactional and marketing emails allows for better control over sender reputation and deliverability.
20 Feb 2023 - SparkPost
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