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Should I use separate IPs or domains for transactional vs marketing emails?
Summary
The overwhelming consensus among email experts, marketers, and documentation from major email service providers is that separating transactional and marketing emails is a critical best practice for maintaining optimal deliverability and protecting sender reputation. This separation can be achieved through dedicated IPs, subdomains, or separate sending domains, with authentication via SPF and DKIM being essential. Transactional emails generally have higher engagement and better deliverability, so isolating them from marketing emails, which can be more prone to deliverability issues, ensures that important transactional messages reach the inbox reliably. Proper IP warm-up is crucial when using dedicated IPs.

Key findings

  • Improved Deliverability: Separating email streams improves deliverability for both transactional and marketing emails by isolating reputation and allowing more targeted management.
  • Protected Sender Reputation: Transactional emails are shielded from potential deliverability issues affecting marketing campaigns, preserving their higher engagement and positive reputation.
  • Enhanced Engagement for Transactional Emails: Transactional emails typically have higher engagement rates (opens, clicks) and fewer spam complaints, contributing to a positive sender reputation.
  • Segmentation Methods: Segmentation can be achieved through dedicated IPs, subdomains (e.g., transactional.example.com, marketing.example.com), or separate sending domains. Choose the method that best suits your resources and email volume.
  • Authentication is Key: SPF and DKIM authentication are essential for each domain and subdomain used to send emails to help establish credibility and improve deliverability.

Key considerations

  • IP Warm-up: If using dedicated IPs, proper IP warm-up is essential to establish a positive sending reputation before sending large volumes of email, especially marketing emails.
  • Segmentation Strategy: Carefully choose the right segmentation method (IPs, subdomains, domains) based on your email volume, infrastructure, technical capabilities, and deliverability goals. Consider the resources required for each approach.
  • Monitoring & Maintenance: Regularly monitor sender reputation and deliverability metrics for each email stream (transactional, marketing) to identify and address any issues promptly. Use tools and dashboards provided by your ESP.
  • Complexity: Consider the technical complexity and ongoing management required to maintain separate IPs or domains. Subdomains might offer a less complex alternative.
  • Bad actors: IP segmentation can help prevent bad actors from affecting all clients.
What email marketers say
11 marketer opinions
The consensus from email marketing experts is that separating transactional and marketing emails is crucial for maintaining optimal deliverability and protecting sender reputation. This separation is typically achieved through dedicated IPs, subdomains, or separate sending domains. Transactional emails generally have higher engagement and better deliverability metrics, and isolating them from marketing emails, which can be more prone to deliverability issues, ensures that important transactional messages reach the inbox reliably.

Key opinions

  • Improved Deliverability: Separating email streams improves deliverability for both transactional and marketing emails by isolating reputation.
  • Protected Sender Reputation: Transactional emails are shielded from potential deliverability issues affecting marketing campaigns.
  • Enhanced Engagement: Transactional emails typically have higher engagement rates, which contribute to a positive sender reputation.
  • Segmentation Methods: Segmentation can be achieved through dedicated IPs, subdomains (e.g., transactional.example.com), or separate sending domains.

Key considerations

  • IP Warm-up: If using dedicated IPs, proper IP warm-up is essential to establish a positive sending reputation.
  • Segmentation Strategy: Choose the right segmentation method (IPs, subdomains, domains) based on email volume, infrastructure, and deliverability goals.
  • Monitoring & Maintenance: Regularly monitor sender reputation and deliverability metrics for each email stream to identify and address any issues promptly.
  • Bad Actors: IP segmentation can help prevent bad actors from affecting all clients.
Marketer view
Email marketer from Mailjet explains that segmenting email traffic based on type (transactional vs. marketing) by using different IPs or domains is a key deliverability best practice. This separation helps maintain a good reputation for transactional emails, ensuring important messages reach the inbox.
21 Nov 2021 - Mailjet
Marketer view
Email marketer from Email Geeks explains that, in general, transactional emails get better engagement, very low spam complaints, and lower bounces leading to better deliverability, hence the hesitation to mix those in with the marketing emails where mileage varies more widely than transactional.
9 Feb 2023 - Email Geeks
What the experts say
6 expert opinions
Experts generally recommend separating transactional and marketing emails using different IPs, domains, or subdomains. This separation is crucial for maintaining deliverability and protecting sender reputation. Transactional emails typically have higher engagement rates and should be isolated from marketing emails to prevent any deliverability issues with the latter from affecting the former. Implementing SPF and DKIM authentication is also essential for each separated stream.

Key opinions

  • Deliverability Enhancement: Separating email streams improves overall deliverability by isolating the impact of marketing emails on transactional emails.
  • Reputation Management: Using separate IPs, domains, or subdomains isolates the sender reputation for each type of email stream.
  • Engagement Impact: Transactional emails have better engagement and should not be mixed with marketing emails, which may have varying engagement levels.
  • Authentication: Authenticating each domain/subdomain with SPF and DKIM is recommended for optimal deliverability.

Key considerations

  • Choice of Separation: Decide whether to use different IPs, domains, or subdomains based on your specific needs and technical capabilities.
  • Reputation Monitoring: Monitor the reputation of each IP, domain, or subdomain to ensure good deliverability.
  • Implementation Complexity: Consider the technical complexity and resources required to set up and manage separate email streams.
Expert view
Expert from Email Geeks shares the general recommendation to split corporate, marketing, and transactional emails into separate domains/subdomains and authenticate them with SPF, DKIM.
23 Dec 2022 - Email Geeks
Expert view
Expert from Email Geeks explains that deliverability can take many forms and reputation is tracked in a few different ways, including IP reputation and domain reputation.
18 Jan 2024 - Email Geeks
What the documentation says
3 technical articles
Leading email service providers like SendGrid, Amazon SES, and Google Workspace recommend separating transactional and marketing emails, ideally using dedicated IP addresses or IP pools. This separation allows for better control over sender reputation, improves deliverability, and isolates any deliverability issues that might arise from marketing campaigns, ensuring that critical transactional emails are reliably delivered.

Key findings

  • Dedicated IPs/Pools: Using dedicated IPs or IP pools is recommended for separating transactional and marketing email traffic.
  • Sender Reputation Control: Separation allows for better control over sender reputation for different email types.
  • Improved Deliverability: Separating email streams improves deliverability for both transactional and marketing emails.
  • Isolation of Issues: Isolates deliverability issues, preventing marketing email problems from affecting transactional emails.

Key considerations

  • Implementation: Setting up and managing dedicated IPs or IP pools requires technical expertise and resources.
  • Sending Patterns: Transactional and marketing emails have different sending patterns and volumes, which should be considered when configuring IP separation.
  • Cost: Dedicated IPs may incur additional costs depending on the email service provider.
Technical article
Documentation from Amazon SES explains that using dedicated IP pools allows you to separate sending reputation for different types of emails. This means you can have one pool for transactional emails and another for marketing emails, isolating any deliverability issues.
19 Aug 2024 - Amazon SES
Technical article
Documentation from SendGrid recommends using dedicated IPs for different types of email traffic, such as transactional and marketing. This allows for better control over sender reputation and can improve deliverability for both types of emails, as their sending patterns and volumes differ.
21 May 2022 - SendGrid
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