Switch from Mailchimp to FlockStack

Before you start

Your contacts move. Your automations, templates and past campaigns don't, and paying readers don't move as paying readers.

• Your contacts. Mailchimp exports an audience as CSV files, and FlockStack reads that export as it comes, with each reader's status and signup date. The import checks the addresses it brings in: invalid and misspelled ones, role addresses, duplicates and anyone who left before. It can also take tags and custom fields.
• Not your automations or templates. They stay in Mailchimp. Step 4 says how to rebuild them.
• Not your past campaigns. FlockStack imports past posts only from Substack, beehiiv, WordPress and Ghost exports.
• Not paying subscribers. FlockStack can't move a paid subscription from Stripe today. Step 6 covers it.

Keep Mailchimp running until your first issue has gone out from FlockStack. You are responsible for having permission to email the readers you import.

1. Export from Mailchimp

Per Mailchimp's help center, as of October 21, 2026: open Audience, choose the audience if you have more than one, select Export audience, and in the pop-up select Export CSV. Mailchimp shows that the export is in progress and emails you when it is ready. The file is also in the export history, under More options, for 30 days. Only an Owner or Admin can export. Menus change, so follow Mailchimp's page if yours differs.

The export is often a ZIP with one CSV for each status, with the status in the file name. The file has your audience fields and columns such as the sign-up time, the member rating, the time zone and a TAGS column. It does not include opens, clicks or purchase history.

2. Choose what to import

Import the subscribed file. Leave out the unsubscribed, cleaned and non-subscribed files: those people shouldn't get your email. Keep them somewhere safe, so you can check that nobody who left is added back. The import API can take a contact with a status of unsubscribed, bounced or complained, and an existing contact keeps its status unless a row gives a stricter one, so a script can bring your suppressed addresses across too.

3. Import your contacts

FlockStack's README lists Mailchimp's CSV export among those it reads as they come, with each reader's status and signup date. Even so, import a small batch first and check the result on the Contacts page: the addresses, the tags and the dates. Then import the rest.

On the Contacts page, choose the import and upload the CSV. An import can add tags, from a column named tags or as one tag for the whole file. Rename Mailchimp's TAGS column to tags first, and tag the whole file as well, for example from-mailchimp, so you can find these readers later. Custom fields are set from columns named after them.

Importing contacts starts no automations, so nobody gets a welcome series. The same import is in the API and the MCP server as import_contacts; it takes a status, a sign-up date and tags on each contact. Moving between platforms in the docs describes it from the app's side.

4. Rebuild your automations

Mailchimp's automation flows don't move. Write down each flow in Mailchimp: what starts it, each email and each wait. Then build it in FlockStack, which starts an automation from 15 triggers and builds it from 10 kinds of step, among them waits, branches, splits and webhooks. Newsletter automation lists them. Mailchimp's Essentials plan has flows of up to 4 steps, and its Standard and Premium plans up to 200 flow points, per its plan comparison, so a long flow may need a closer look before it is rebuilt.

Your segments don't move either. Tags come across on import, and a newsletter can save up to 50 segments in FlockStack, built from 13 kinds of condition.

5. Your past campaigns

Mailchimp's campaign archive stays behind. If a page you want to keep exists only there, save its text yourself, and paste it into a new issue in FlockStack.

6. Paying readers

Mailchimp's pricing pages list no paid newsletter feature, so a Mailchimp list often has no paying readers at all. If yours does, through another service, FlockStack can't attach a subscription that exists elsewhere to a contact. Those readers subscribe again, in four steps:

1. Set up your paid tier on the Payments page and connect Stripe. The paid newsletter platform page explains each step.
2. Tag those contacts paying-elsewhere before you import them, and make a segment from the tag.
3. Send that segment an issue that explains the move and links to your subscribe page.
4. Cancel their subscriptions in the old service once they have moved, so nobody pays twice.

7. Send your first issue

Start with the same kind of issue you sent on Mailchimp. FlockStack warms up your sending: contacts you have never emailed go out as a first slice of 5% of the list (at least 200 and at most 2,000 contacts), and the rest follows after 3 hours if the slice's bounces and complaints stay low. Set up your sending domain on the Domains page first, so the email comes from your own address, and read SPF, DKIM and DMARC for newsletters for what the mailbox providers ask of senders.

8. Close or downgrade Mailchimp

Per Mailchimp's help center, a plan's contact limit counts subscribed, unsubscribed and non-subscribed contacts, and the bill follows the peak total in the billing period. Moving your list doesn't lower the current period's bill, so check your billing date and downgrade or close the account before the next one. Mailchimp's Free plan holds 250 contacts, if you want to keep a small audience there.

Where FlockStack is the weaker pick

If you rely on Mailchimp's SMS add-on, its integrations or its advanced segmentation and long automation flows, FlockStack may not replace them. FlockStack vs Mailchimp compares the two with dated sources. FlockStack is open source under the AGPL-3.0 at github.com/ankurmans/flockstack, so the next move, if you ever want one, is yours to make: account export writes your contacts as a CSV and every issue as Markdown and HTML.