Will you experience deliverability issues when moving an email list to Substack?
Matthew Whittaker
Co-founder & CTO, Suped
Published 25 Jul 2025
Updated 26 Aug 2025
5 min read
The decision to move an email list to a new platform like Substack often comes with questions about deliverability. Will your emails still reach the inbox? Do you need to go through a warm-up process? These are valid concerns, as email deliverability is a complex ecosystem where even small changes can have noticeable impacts. Let's explore what happens when you transition your audience to Substack and how to navigate potential challenges.
Migrating an email list always introduces variables that can affect how mailbox providers perceive your sending. Factors like your historical sender reputation, list hygiene, and how the new platform handles email authentication all play a role. Understanding Substack's approach to email sending is key to anticipating and preventing issues.
Substack's unique email sending environment
Substack operates differently from many traditional Email Service Providers (ESPs). For most users, emails are sent from Substack's own domains and shared IP addresses. This means that Substack itself is responsible for managing the technical aspects of email authentication, like SPF, DKIM, and DMARC, for its platform-wide sending. You typically do not have direct control over these records unless you configure a custom domain.
Because Substack handles the sending infrastructure, a traditional IP warm-up process, where you gradually increase sending volume from a new IP, is generally not something you need to manage directly. Substack's robust infrastructure aims to ensure high deliverability for its users. However, this doesn't eliminate all deliverability concerns for you.
The platform's overall reputation impacts everyone sending through it. If other Substack writers experience high spam complaints, it could theoretically affect the shared sending reputation. Conversely, Substack's efforts to maintain a healthy sending environment generally benefit its users, which is why some creators report good deliverability on the platform.
Preparing your list for the move
Regardless of the email platform, your email list's health is the most significant factor in deliverability. Moving a stale or unengaged list to Substack (or any ESP) can lead to immediate deliverability issues, regardless of the platform's reputation. It's crucial to clean your list before migrating.
Pre-migration list cleaning checklist
Remove inactive subscribers: Segment your list and remove subscribers who haven't opened or clicked in a long time (e.g., 6-12 months).
Verify email addresses: Use an email verification service to identify and remove invalid or non-existent email addresses. This prevents hard bounces.
Check for spam traps: Be diligent about list acquisition methods to avoid spam traps, which can severely damage your reputation. A clean list reduces the risk of hitting these.
Confirm consent: Ensure all subscribers on your list have explicitly opted in to receive your emails. Substack takes spam complaints seriously.
Ignoring list hygiene before migrating can lead to an increase in bounces, spam complaints, and a hit to your overall sender reputation, even on a platform with good baseline deliverability like Substack.
Navigating the migration process
When moving your list, it's wise to set expectations for your subscribers and yourself. Inform your audience about the platform change. If your 'from' address will be different, let them know in advance. This transparency can prevent confusion and reduce the likelihood of your emails being marked as spam.
Typical ESP (e.g., Mailchimp)
With most ESPs, you often have more granular control over your sending infrastructure. This can include managing your own dedicated IPs, configuring custom DNS records, and performing your own IP warm-up if needed. Metrics might include detailed bounce and complaint rates tied directly to your sending.
Substack
Substack simplifies the technical side, abstracting much of the deliverability management. You typically send from their shared IP space and domain. If you opt for a custom domain, you might need to handle some DNS configurations. Substack's platform-wide reputation is a major factor, and their analytics provide insights into your individual publication's performance.
When importing your list, follow Substack's guidelines carefully. They explicitly state that spam complaints can damage deliverability for their entire community, making a clean, consented list paramount. While direct IP warm-up isn't usually necessary, a gradual reintroduction of your list (especially if it's large and hasn't been engaged recently) can help. Send your first few newsletters to your most engaged segments before sending to the entire list.
Post-migration monitoring and engagement
After migrating, closely monitor your engagement metrics. While initial open and click rates might appear lower on a new platform, this isn't always a deliverability issue but rather a change in how metrics are tracked or how your audience adapts. Focus on trends over time rather than day-to-day fluctuations.
Keep an eye on any bounce rates or spam complaints within Substack's analytics. High complaint rates can lead to your emails being directed to spam folders or even blocklisted (blacklisted). Regularly check if your domain or any associated IPs are on email blocklists (blacklists) as an additional safeguard. Although Substack manages the underlying infrastructure, your sending practices still directly impact your publication's reputation within the platform and with mailbox providers.
Example DMARC record (for understanding, Substack manages this for you)DNS
While Substack handles many technical aspects, your content quality and subscriber engagement remain your responsibility. Engaging content, clear calls to action, and prompt responses to subscriber feedback can help maintain a positive sender reputation and ensure long-term deliverability. Resources on email deliverability issues often emphasize the importance of these foundational elements.
A smooth transition to Substack
Moving an email list to Substack doesn't automatically guarantee deliverability issues, but it's not entirely without risk. The key is thorough preparation, particularly regarding list hygiene, and understanding Substack's operational model. By cleaning your list, communicating with your subscribers, and maintaining engaging content, you can set yourself up for a smooth transition and continued success in reaching your audience's inboxes.
While Substack manages the technical backbone of email sending, your proactive steps in list management and content creation are ultimately what will sustain your deliverability on the platform.
Views from the trenches
Best practices
Always clean your email list thoroughly before migrating to a new platform like Substack.
Inform your subscribers about the platform change and any new 'From' address to avoid confusion.
Gradually reintroduce your list by sending initial newsletters to your most engaged subscribers first.
Focus on creating high-quality, engaging content that encourages opens and clicks to maintain good sender reputation.
Common pitfalls
Migrating an uncleaned or stale list, leading to high bounce rates and spam complaints.
Not setting clear expectations with subscribers about the change, causing emails to be marked as spam.
Overlooking the importance of engagement metrics on the new platform, assuming a direct comparison to the old ESP.
Failing to monitor deliverability dashboards and feedback loops for signs of issues.
Expert tips
If using a custom domain on Substack, you might need to handle DNS records, but generally, Substack manages the sending infrastructure.
Initial open and click rates on a new platform can be lower, which isn't always a fault of the platform but a change in tracking.
Substack's collective sender reputation depends on all users maintaining good sending practices.
Mailbox providers like Microsoft can be sensitive to new sending patterns, especially during migrations.
Expert view
Expert from Email Geeks says that any time you switch platforms, you should warm up your list, unless it is very small. It's common for initial open and click rates to be lower, which is not necessarily the platform's fault.
2025-08-13 - Email Geeks
Marketer view
Marketer from Email Geeks says that if you are following all deliverability best practices, you should likely be fine on Substack, provided you are placed in a healthy IP pool with good neighbors.
