Switching guides
Bring your newsletter to CodeOutbox
Export your subscribers as a CSV, import it as-is, and swap your signup form. People who already opted in stay subscribed. Most moves take about ten minutes.
From MailchimpMailchimp keeps subscribed, unsubscribed and cleaned contacts in one audience. You only need the subscribed ones.
From KitKit can export only your confirmed subscribers, which is exactly the list you want to bring.
From SubstackSubstack lets you export your mailing list as a CSV from the subscriber dashboard.
From ButtondownButtondown exports every subscriber with their type, so CodeOutbox can tell who's still active.
From anywhere else
Any CSV with an email column works, including a spreadsheet export. Common headers like Email Address, First Name and Status are recognized, unsubscribed and bounced rows are left out, and other columns become merge fields. Import it under Lists → Import subscribers, or with npx codeoutbox import <list> <file.csv> --confirmed.
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