A migration is a communications project, not just a CSV upload. Preserve the list, explain the change, and test the first send before turning off the old publication.
Before you export
Record your current signup language, consent context, active and unsubscribed states, tags, paid status, publication URLs, and the posts that readers actually use. Keep a copy of the original export.
The documented beehiiv path
beehiiv documents importing free Substack content by URL and uploading a CSV for subscribers. Its import guidance also describes duplicate and inactive-email filtering, so compare accepted and rejected counts after the import.
Send a migration message
Tell readers where the new publication lives, why the move is happening, what changes, and how to leave. Run a test send to addresses you control before sending to the full list.
Use this checklist
- Export the Substack list and content archive.
- Record consent, paid status, and unsubscribed contacts separately.
- Import a small test file first.
- Compare accepted, rejected, and duplicate counts.
- Publish a migration notice before changing signup links.
Read the official product information
These are direct canonical links. Pricing, plan boundaries, and program terms can change; confirm them at the source before you act.