Should I separate transactional and marketing emails?

Key findings

• Reputation isolation: Transactional emails, by nature, generally have higher engagement rates and are less likely to be marked as spam, which contributes to a positive sending reputation. Marketing emails, however, carry a higher risk of complaints and low engagement, which can negatively impact reputation. Separating them ensures that any negative impact from marketing sends does not affect the delivery of essential transactional messages.
• Improved deliverability: Inbox providers, such as Gmail and Outlook, monitor sending behavior and reputation closely. By distinguishing between email types, they gain a clearer understanding of your sending practices, which can lead to better inbox placement for both categories. If you're experiencing issues, knowing how to troubleshoot transactional emails going to spam becomes easier when send streams are separate.
• Reduced risk of blocklisting: A low-performing marketing campaign or a sudden spike in spam complaints can land your sending IP or domain on a blocklist (or blacklist). If both email types share the same infrastructure, transactional emails also suffer, potentially halting critical communications. Maintaining separate domains and IP addresses for these types of mail is a key strategy for avoiding being placed on an email blocklist.
• Compliance: Regulatory frameworks like CAN-SPAM often have different requirements for transactional versus marketing emails, particularly concerning opt-out mechanisms. Separation helps ensure compliance with these regulations.

Key considerations

• Volume considerations: While separation is ideal, it requires sufficient email volume for both streams to establish a consistent sending history and build reputation on their respective IPs. Very low volume on a dedicated IP can sometimes be less effective than sending from a well-managed shared IP pool. More on using separate IPs or domains.
• Subdomain and IP strategy: It is generally recommended to use different subdomains (e.g., transactional.yourdomain.com and marketing.yourdomain.com) and potentially different dedicated IPs or at least separate shared IP pools provided by your Email Service Provider (ESP). Mailgun provides further details on this distinction.
• Sender reputation management: Regardless of separation, maintaining strong sender reputation for all email streams is paramount. This includes proper list hygiene, sending relevant content, and monitoring engagement. You can learn more about using separate subdomains for transactional and promotional emails.
• Strategic decision: The decision to separate should be based on your specific sending volume, audience engagement, and risk tolerance. For businesses with high volumes of both types of emails, separation is almost always beneficial.

Key opinions

• Crucial separation: Many marketers view separating transactional and marketing emails as a fundamental best practice for optimal deliverability. It is not considered an outdated approach but rather a modern necessity for effective email programs.
• Reputation protection: The primary driver for separation is to protect the high-reputation stream of transactional emails from the potentially lower reputation (due to complaints or low engagement) of marketing emails. This ensures that critical customer communications are not impacted.
• Volume dependency: While separation is ideal, some marketers acknowledge that it may not be feasible for very low sending volumes where a single IP cannot sustain enough traffic to build two distinct reputations. In such cases, extreme care must be taken with marketing sends.
• Good sender behavior: Regardless of whether streams are separated or combined, being a 'good sender' is critical. This involves strict adherence to opt-in practices, segmentation, and sending relevant, engaging content. This proactive management helps prevent email deliverability issues.

Key considerations

• Subdomain and IP usage: Marketers frequently recommend using separate subdomains (e.g., alerts.yourdomain.com for transactional and news.yourdomain.com for marketing) and, whenever possible, dedicated IP addresses for each stream.
• Shared IP pools: For lower volumes, using different shared IP pools (potentially from different ESPs) for transactional and marketing emails can be a viable alternative to dedicated IPs, offering some degree of separation without requiring high individual volume. This can also help with splitting sends to engaged users.
• Impact of poor marketing practices: If marketing and transactional emails are combined on a single sending domain or IP, poor marketing practices (e.g., sending to unengaged subscribers, high complaint rates) will directly jeopardize the deliverability of transactional emails. LuxSci explains how separating helps ensure reliable delivery.
• Strategic planning: Marketers should plan their email infrastructure to accommodate this separation from the outset, especially for growing businesses, to avoid complex migrations or deliverability issues down the line.

Key opinions

• Best practice: Experts overwhelmingly agree that separating transactional and marketing emails is a crucial best practice for maintaining optimal deliverability and sender reputation.
• Reputation segregation: The core reasoning is to allow each email type to build and maintain its own sender reputation. Transactional emails, being expected and often critical, tend to generate positive engagement, whereas marketing emails, being unsolicited, face higher scrutiny and risk.
• IP and subdomain differentiation: A key recommendation is to use distinct subdomains (e.g., reply.yourdomain.com vs. promo.yourdomain.com) and, where volume permits, separate dedicated IP addresses for each stream. This provides the clearest signal to MBPs.
• Handling low volume: For organizations with insufficient combined volume to support two dedicated IPs, experts advise doubling down on exemplary marketing sending practices. This minimizes negative impact on transactional emails if they must share resources. This is particularly relevant when deciding whether to segregate sending IPs by recipient domain.

Key considerations

• Long-term strategy: Implementing separation is a long-term strategic decision. It helps to future-proof email programs against evolving deliverability filters and maintain consistent performance for critical communications.
• Monitoring and adjustment: Even with separation, continuous monitoring of sender reputation, engagement metrics, and blocklist status for both streams is vital. This allows for timely adjustments to sending practices.
• ESP capabilities: The choice of Email Service Provider (ESP) is important, as some offer better options for managing multiple subdomains and IP pools than others. This is a common discussion point, for example, regarding SFMC's transactional email label.
• Authentication alignment: Ensure that email authentication protocols (SPF, DKIM, DMARC) are correctly configured for each subdomain to maximize deliverability and align with current best practices. Word to the Wise offers insights into why separating IP addresses is crucial.

Key findings

• Purpose-driven separation: Documentation highlights that transactional emails are typically triggered by user actions and provide essential, non-promotional information, whereas marketing emails are promotional and often sent to a larger audience. This fundamental difference necessitates separate handling.
• Reputation management: Email providers analyze sending patterns and user engagement for each sender. Separating streams helps them accurately assess the sender's reputation for each type of mail, preventing low engagement or complaints from marketing emails from affecting transactional delivery.
• IP and domain best practices: Official guidelines often recommend using distinct subdomains and, ideally, separate dedicated IP addresses for transactional and marketing sends. This provides a clear signal to recipient servers about the nature of the email content and helps isolate deliverability risks.
• Compliance implications: Documentation frequently touches upon the varying compliance requirements (e.g., unsubscribe links) for transactional versus marketing emails. Separation simplifies adherence to these legal distinctions.

Key considerations

• Consistent sending: To build a strong reputation on a new IP or subdomain, consistent sending volume is necessary. Documentation implies that if volume is too low for separate dedicated IPs, a well-managed shared pool, perhaps even with a different ESP, might be a more practical initial step.
• Monitoring sender reputation: Regardless of separation, documentation stresses the importance of regularly monitoring sender reputation metrics for both streams using tools like Google Postmaster Tools or other analytics provided by ESPs.
• Authentication standards: Proper implementation of email authentication (SPF, DKIM, DMARC) for each sending domain/subdomain is critical for deliverability. Google's sender guidelines specifically advise separating mail by purpose.
• Content and recipient engagement: Documentation often notes that even with separation, maintaining high-quality content and targeting engaged recipients are paramount for both transactional and marketing emails to achieve optimal inbox placement.