How do email list imports work?

We always welcome writers coming to Substack from other services and recognize that you've worked hard to build your list over time. As a platform dedicated to helping writers build trusting relationships with their readers, we take the quality of imported email lists seriously. 


Spam complaints can damage deliverability for our entire writer community and prevent publishers from reaching their audiences. 

If we receive reports that a publication imported readers who had not opted in, we may take actions to restrict or disable publishing abilities. 

How do imports work? 

Substack has a number of detection mechanisms in place to assess how risky your import list might be. If these detection mechanisms indicate that your email list contains recipients who have not explicitly opted in to receiving messages from you and are therefore likely to mark your emails as spam, your publication and list may be flagged for review by our Trust and Safety team. 

If your import was flagged for review, there are several ways to increase the likelihood of it being approved quickly. 

Be open and honest. It's important to provide the origin of a list. We require that lists contain only those who have explicitly opted in to receiving messages from your publication. Collections of contacts, leads, or other sources where all participants did not opt in are likely to be denied. 

Make sure your entire list has opted in. Before importing a large list, you might want to send your recipients an email asking them to explicitly opt in to receive emails through Substack. If you prefer, you can embed a signup form for your readers to manually opt in by following these steps

Provide as much information as possible. When importing your list, you may be prompted to answer optional questions about your list, including a URL for where your readers opted in. Voluntarily answering all of these questions will increase the likelihood that your list is approved. 

How long will it take for my list to be approved? 

Our Trust and Safety team works hard to ensure your list is reviewed within 72 hours, but there may be rare occasions when high import volume could cause additional delays. We appreciate your patience as we work to keep Substack free from spam and abuse.  

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