Summary
The decision to separate marketing and transactional email streams onto different IP addresses or subdomains is a common deliverability question. While it is often cited as a best practice, especially for larger senders, the necessity and benefits depend heavily on specific sending volumes, list hygiene, and overall email program management. For lower volume senders or those with excellent reputation, combining streams might be acceptable, but for most, separation offers a crucial layer of protection against reputation damage. Understanding how to manage your domain reputation is key.
Key findings
- Separation: Separating marketing and transactional email streams is generally considered a best practice for deliverability protection.
- Reputation Impact: Transactional emails typically have higher engagement and lower complaint rates, safeguarding their delivery from potential issues with marketing emails.
- Subdomain Use: Using separate subdomains helps isolate the reputation of different email types, even if sent from the same IP, although separate IPs offer stronger isolation.
- Volume Sensitivity: Low sending volumes (e.g., 100k emails/month) might not justify a dedicated IP for each stream, making shared IPs or a combined approach a viable option if reputation is currently good.
Key considerations
- Current Deliverability: If you are not experiencing any deliverability issues, changing your setup might not be necessary. Unnecessary changes can sometimes introduce new problems.
- Process Quality: Strong internal processes for list hygiene, permission management, and content quality can mitigate the risks of combining streams.
- Cost vs. Benefit: Consider the operational overhead and cost of managing multiple IPs or subdomains versus the potential deliverability gains. For smaller volumes, shared IPs might be more practical for marketing sends.
- ISP Evolution: ISPs (Internet Service Providers) are increasingly sophisticated at filtering mail based on factors beyond just IP address, such as domain reputation and content, reducing the absolute necessity for IP separation in all cases. Mailgun's blog post highlights how separating subdomains affects domain reputation.
What email marketers say
Email marketers often find themselves weighing the conventional wisdom of separating email streams against practical considerations of volume and existing performance. While a common recommendation exists, many marketers also note that successful deliverability can be achieved even when combining marketing and transactional emails, provided other strong practices are in place. The core concern revolves around protecting the highly critical transactional emails from the potentially fluctuating reputation of marketing campaigns.
Key opinions
- Conditional Separation: Many marketers successfully send both commercial and transactional emails from one IP and the same sending domain, particularly if good processes are in place.
- Low Volume Concerns: There are concerns about maintaining a dedicated IP's reputation with very low volumes (e.g., 100k emails/month) for combined streams.
- Subdomain Strategy: Some marketers question whether setting up at least one subdomain for sending is always beneficial, even if not splitting streams by IP.
- Transactional Resilience: Transactional emails are inherently less likely to generate abuse complaints than marketing messages because they are expected, though exceptions exist.
- Domain Recognition: Leveraging a subdomain of your branded domain can capitalize on existing brand recognition and customer relationships.
Key considerations
- Current Performance: If there are no existing deliverability problems, maintaining the current setup may be the most prudent course of action.
- Reputation Protection: Separating promotional emails to a dedicated subdomain can help prevent their reputation from affecting other email types.
- Engagement Tracking: Subdomains can make it easier for marketers to track the deliverability and engagement of different types of email campaigns.
- Deliverability Insights: Utilizing separate subdomains for various email types allows for more granular insights into how each stream performs and contributes to overall sender reputation, as discussed by SendLayer in their subdomain guide.
Marketer view
Email marketer from Email Geeks shared their situation, explaining that their company sends approximately 100,000 emails per month from a single dedicated IP address, which handles both marketing and transactional messages. They were concerned about whether this setup aligns with best practices and if a low volume dedicated IP is sustainable. They sought advice on potential improvements.
Marketer view
A marketer from WP Mail SMTP advises having a separate subdomain specifically for promotional emails. This separation is crucial to prevent the reputation of your marketing campaigns from negatively impacting the deliverability of your more critical transactional emails, ensuring their reliable arrival in the inbox.
What the experts say
Email deliverability experts offer nuanced perspectives on separating email streams. While acknowledging the historical basis for separation (namely, protecting transactional mail from poor marketing practices), many emphasize that modern ISP filtering is more sophisticated, focusing heavily on domain reputation and engagement signals beyond just IP addresses. Experts often advise against changing a working system and highlight that the 'best practice' is often a defensive measure rather than a universal necessity, contingent on the sender's overall program health.
Key opinions
- Volume Thresholds: Sending 100,000 emails a month is often considered a small volume for a dedicated IP, suggesting that shared IPs might be more suitable if considering a split.
- Defensive Strategy: Separating IPs is often a defensive practice, primarily intended to prevent poor marketing behavior (e.g., high complaints, low engagement) from damaging critical transactional messaging.
- Modern Filtering: Consumer ISPs have significantly improved their filtering capabilities over the past 15 years, relying less on IP addresses and more on other factors, which reduces the need for strict IP-based stream separation.
- Reputation Stability: Even very low-volume dedicated IPs can successfully create and maintain a good reputation, indicating that minimum volume is less of an issue than it once was.
- Complaint Nuance: While transactional emails are generally less prone to abuse complaints, these complaints are a natural part of sending, and low rates for wanted mail typically do not cause significant problems.
Key considerations
- Evaluate Current State: If no delivery problems exist, there is no immediate reason to change the current email sending setup.
- Process Quality: Good internal processes for managing email sends can negate the need for separation, even for high-volume senders combining streams.
- Context is Key: The determination of what constitutes 'best' practice for separating IPs or subdomains depends on a multitude of factors specific to each email program.
- Cold Email Isolation: For clients with significant delivery problems and active cold email programs, aggressive isolation using entirely separate domains (and even Google Workspace accounts) is recommended to protect legitimate business and opt-in mail, as explored in articles like those on SMTP.com about stream separation.
Expert view
An expert from Email Geeks suggests that a volume of 100,000 emails per month is quite small to warrant a dedicated IP address. However, they affirm that when email volumes are sufficiently high, separating marketing and transactional emails becomes an absolute best practice for maintaining optimal deliverability and sender reputation.
Expert view
Expert from Word to the Wise explains that the fundamental reason for recommending separate IPs for marketing and transactional emails stems from a lack of complete trust in internal teams to consistently secure recipient permission. This separation acts as a safeguard, preventing potentially damaging behavior from marketing sends from impacting critical transactional messaging.
What the documentation says
Official documentation and guides from email service providers and industry bodies often advocate for separating marketing and transactional emails. This recommendation stems from the fundamental difference in expected engagement and the potential for a negative reputation from one stream to compromise the critical delivery of the other. They highlight how separation can protect deliverability, improve speed, and ensure important communications reach their intended recipients without being caught in spam filters designed for promotional content.
Key findings
- Reputation Isolation: Separate subdomains allow for distinct reputation management, ensuring that issues with marketing emails do not impact transactional emails.
- Delivery Priority: Transactional emails, due to their importance and expected nature, benefit from a dedicated sending infrastructure to maximize delivery speed and inbox placement.
- Reduced Spam Risk: Sending transactional emails from separate IPs or subdomains helps them bypass spam filters that are primarily designed to catch commercial content.
- User Experience: Improved delivery speed for transactional messages contributes directly to a better user experience and higher satisfaction.
Key considerations
- Impact on Reputation: Using the same domain for both marketing and transactional emails can lead to deliverability problems if marketing efforts generate complaints or low engagement.
- Authentication Practices: Ensure that transactional emails have strong authentication regardless of IP or subdomain separation.
- Strategic Subdomain Naming: Name transactional subdomains clearly (e.g., 'orders.yourcompany.com') to indicate their nature and help them bypass spam filters, as suggested by Benchmark Email's subdomain guide.
Technical article
Documentation from SAP Community highlights that implementing a separate transactional subdomain can significantly enhance email delivery speed. This improvement in delivery directly contributes to a superior user experience and higher overall satisfaction for recipients of critical communications.
Technical article
Documentation from Mailmodo advises that transactional emails should be sent from a distinct domain and IP address. This separation is intended to protect these critical messages from any negative reputation fallout associated with bulk marketing emails, ensuring their reliable delivery.
Related resources
15 resources
Related pages
Should I use separate subdomains for marketing and transactional emails?
Should I use separate email subdomains for transactional and promotional emails, and how does engagement affect this?
Should I separate transactional and marketing emails?
Do transactional emails negatively impact marketing email deliverability, and is it necessary to use separate IP addresses for them?
Why use subdomains for email marketing deliverability?
Should I use separate IPs or domains for transactional vs marketing emails?
A practical guide to understanding your email domain reputation
How long does it take to recover domain reputation from Bad/Low to High
Should operational emails be sent from a marketing subdomain or transactional subdomain?
When should I use subdomains for email sending and how do they affect my reputation?
