Switch from Substack to FlockStack

Before you start

Your subscribers and your posts move. Your old links can follow. Your paying readers don't move as paying readers.

• Your subscribers. FlockStack reads the CSV that Substack exports. The import reads each address and its status, and the signup date and other columns when the file has them, and checks the addresses it brings in: invalid and misspelled ones, role addresses, duplicates and anyone who left before.
• Your published posts. Each becomes an issue already marked as sent, dated as before, with its title, subtitle or excerpt, slug, author, text, links, tables and pictures. No email goes out.
• Your old links, if your newsletter was on your own domain.
• Not your paying readers, as paying readers. FlockStack can't move a paid subscription from Stripe today. Step 4 shows how to bring them across.

Keep Substack running until your first issue has gone out from FlockStack and your paying readers have moved. Readers whom Apple bills for a paid Substack subscription can't be moved: Substack's in-app purchase FAQ says Apple doesn't transfer billing relationships, so invite them to subscribe again.

You are responsible for having permission to email the readers you import.

1. Export from Substack

Subscribers. Export your subscriber list from your Substack dashboard; Substack's features page lists a full data export that includes it. Substack's help center has the current steps, and its menus can change. FlockStack reads the export as it comes, so there is nothing to convert. The one change you may want is the tags column in step 2.

Posts. FlockStack's moving guide, read on October 20, 2026, says to open Settings in Substack, then Import/Export, and start an export; menus can change. It says Substack gives you a ZIP with your posts in it. Upload the whole ZIP as you received it, without opening it. Files up to 40 MB are read.

2. Import your subscribers

On the Contacts page, choose the import and upload the CSV. An import can add tags, from a tags column or as one tag for the whole file. Tag the whole file, for example from-substack, so you can find these readers later. If you know who pays on Substack, add a tags column to the file first and put paying-elsewhere on those rows. Step 4 uses it. 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. Moving between platforms in the docs describes it from the app's side.

3. Import your posts

In the dashboard, open Settings, then Import posts. Choose the file and select Read the file: you see a preview with the count of published posts, the count of paid posts and the newest titles. Nothing is imported until you select Import. It runs in the background, and FlockStack emails you a report when it finishes.

Imported posts are not counted in your monthly emails, because none is sent. Posts that were paid on Substack become issues for paid readers, which show a teaser on your website. You need a paid tier set up for readers to get them. From the API or the MCP server, create_post_import reads the file, start_post_import starts it and get_post_import shows progress.

The number of posts and pictures one import reads depends on your plan, newest posts first. The limits are in the moving guide.

4. Bring your paying readers across

FlockStack sells subscriptions through your own Stripe account, and it can't attach a subscription that exists on another platform to a contact. A reader who pays on Substack comes in from the import as an ordinary active reader. They 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. Make a segment of the contacts tagged paying-elsewhere, from step 2.
3. Send that segment an issue that explains the move and links to your subscribe page.
4. Cancel their subscriptions on Substack once they have moved, so nobody pays twice. That is a step for Substack's help center and for your Stripe account.

5. Keep your old links working

If your Substack newsletter lives on your own domain, FlockStack can answer for the old addresses:

1. On the Domains page, add your domain and enter the website address your old site used, for example news.example.com.
2. At your DNS provider, point that record at the CNAME shown on the Domains page, replacing Substack's record. Remove any A or AAAA records on that name.
3. Select Check on the Domains page. When it passes, each old address redirects to the matching issue with a permanent redirect.

An address on Substack's own domain, such as yourname.substack.com, can't be redirected, and a root domain such as example.com can't point to FlockStack, so its old links stay with Substack. For anything else, add redirects one by one under Settings, then Redirects, or upload a CSV with from,to rows.

6. Send your first issue

Start with the same kind of issue you sent on Substack. 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.

Where FlockStack is the weaker pick

Substack's network stays with Substack, and FlockStack has only an opt-in recommendations directory. Check what your Substack export contains, because Notes followers and app-only readers may not be in it. FlockStack vs Substack compares the two with dated facts. 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.