What is the deliverability impact of using subdomains vs sub-subdomains in email marketing?
Summary
What email marketers say9Marketer opinions
Email marketer from SparkPost recommends using subdomains to separate different types of mail streams (e.g., transactional, marketing) to maintain a good sender reputation for each type of communication.
Email marketer from Email Geeks explains that as an ESP, they like to use the subdomain for signing and sub-subdomain for tracking. This allows the customer to enter one set of NS records, and the ESP can manage all the DNS settings, secure tracking links, etc., from there. Some customers use the subdomain for signing in the 5322.from, which can be useful for reply management features.
Email marketer from StackExchange user explains that the deliverability impact is correlated to how your audience engage with your email. if you do not segment your email sending, and send everything from one domain/IP, it can be marked as spam more often - however if you segment it and send from multiple subdomains it means one subdomain can be marked as spam without impacting your entire business.
Email marketer from GMass explains that you should use a process of warming up your subdomains when you use them - to avoid being marked as spam and impacting deliverability. You will be able to gradually improve its sender reputation with mailbox providers.
Email marketer from SendGrid explains that using a dedicated subdomain for email sending helps to build a separate reputation from your main domain. This is particularly useful for transactional vs marketing emails.
Email marketer from Neil Patel shares that using subdomains for email marketing can help segment your audience and improve deliverability. By separating your email traffic onto different subdomains, you can protect your main domain's reputation.
Email marketer from Reddit user u/EmailPro explains that they use subdomains to separate marketing blasts from transactional emails. This ensures the main domain's reputation is protected in case of a marketing campaign issue.
Email marketer from Mailjet shares that a well-planned subdomain strategy, separating different types of email traffic (e.g., marketing, transactional) onto separate subdomains, can improve deliverability by isolating reputation issues.
Email marketer from Email Geeks shares that from a deliverability perspective, it probably doesn’t make much of a difference, though they can see some use cases and organizational methods that would benefit from it, like assigning a subdomain to a specific ESP and then further subdividing the mail streams being sent by that ESP onto sub subdomains.
What the experts say3Expert opinions
Expert from Email Geeks explains that deliverability-wise, there is no specific benefit in using a sub-subdomain compared to a subdomain.
Expert from Word to the Wise discusses the importance of managing the reputation of each subdomain separately. They explain that a poor sending reputation on one subdomain can negatively affect the deliverability of emails sent from other subdomains within the same domain.
Expert from Spam Resource explains that when using subdomains, it's important to implement authentication protocols (SPF, DKIM, DMARC) correctly on each subdomain to ensure optimal deliverability. They state that incorrect setup of these protocols on subdomains can negatively impact email delivery.
What the documentation says5Technical articles
Documentation from RFC Editor (RFC 4406) explains that subdomains can be used to differentiate sending streams for Sender ID validation, potentially impacting deliverability based on sender reputation.
Documentation from Google Workspace Admin Help explains that using subdomains allows for more granular control over SPF and DKIM records, which can enhance email authentication and improve deliverability.
Documentation from Dmarc.org explains that Subdomains are commonly used to align emails with DMARC, which is necessary for passing authentication checks and ensuring better deliverability.
Documentation from Microsoft Learn details how SPF records are evaluated based on the domain in the `MAIL FROM` address, indicating that using different subdomains can require different SPF configurations, which impacts deliverability.
Documentation from Amazon Web Services provides guidance on setting up SPF and DKIM for your subdomains when using them for email sending. Proper configuration is essential for achieving good deliverability.