Moving from Substack, beehiiv, WordPress or Ghost

Files up to 40 MB are read. A ZIP with one of these files inside works too.

In the dashboard, open Settings, then Import posts, pick the file and press Read the file. You see how many published posts it has, how many are for paid subscribers and the newest titles. Nothing is imported until you press Import. It runs in the background: you can close the page, and we email you the report.

From the REST API or MCP, create_post_import reads the file (as base64 under 10 MB, or an https:// link) and answers with the preview, start_post_import starts it and get_post_import follows it.

curl -X POST $FLOCKSTACK_URL/api/v1/post-imports \
  -H "Authorization: Bearer $FLOCKSTACK_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"url": "https://example.com/substack-export.zip"}'

curl -X POST $FLOCKSTACK_URL/api/v1/post-imports/<id>/start \
  -H "Authorization: Bearer $FLOCKSTACK_API_KEY"

• Each published post becomes an issue already sent on its original date, listed on your website. No email goes out and nothing counts toward your month's emails; its stats stay at zero.
• Its title, its subtitle or excerpt (the preview text), its address's slug and its author. Slugs are unique across FlockStack, so a slug someone else has gets a number at the end, and its old address redirects there. An author who isn't your newsletter's keeps their name on the issue.
• The text, cleaned like the editor's: headings, paragraphs, lists, quotes, links, tables and pictures stay; the old platform's styles, scripts, signup forms and placeholders go.
• Pictures are copied to FlockStack's CDN, 4 MB each at most and 10,000 per import. One that can't be fetched keeps its old address and is counted in the report.
• Posts for paid subscribers become issues for your paid readers: the website shows a teaser. Set up your paid subscription so readers can subscribe to read them.

• Subscribers: download them from the old platform and use the contact import on the Contacts page (or import_contacts), which reads Substack's, beehiiv's and Ghost's files as they are.
• Paid subscriptions: moving them from your Stripe account is a separate feature, coming next.
• Drafts, pages, podcasts and their audio, comments, tags, and embedded videos, polls and posts, which keep only their text or link.

On FlockStack Cloud each plan caps the new posts one import adds, the newest first, and what the pictures of all your imports may weigh together. Posts past the cap are counted in the report. A self-hosted server has no caps.

Importing the same file again is safe: posts you already imported are skipped, so it only adds what is missing.

Each imported post gets a redirect from its old address (Substack: /p/<slug>; beehiiv: /p/<slug>; WordPress: the post's permalink, like /2023/05/12/hello-world/; Ghost: /<slug>/) to its new page. They work once the old address points at FlockStack:

1. On the Domains page, add your domain, and as the website's address enter the one your old site used, like news.example.com.
2. At your DNS provider, change that name's record to the CNAME the Domains page shows, in place of the one that pointed at Substack, beehiiv, WordPress or Ghost. Remove any A or AAAA records on the same name.
3. Press Check on the Domains page. Once it's verified, your website answers on that address and every old link lands on its issue with a permanent redirect (301), which search engines follow.

Addresses the old platform owns, like yourname.substack.com, can't point anywhere else, and a site at the root of a domain (example.com) can't point at FlockStack: their old links stay with the old platform.

Add your own redirects in Settings, under Redirects, one at a time or as a CSV of from,to rows (1,000 a file), or with add_redirect and import_redirects. A path matches without case, query or trailing slash, and a redirect keeps the visitor's query string. Your website's own pages (/, /feed.xml, /shop, /subscribe) can't redirect. A website has 25,000 redirects at most, and a change shows within a minute.

from,to
/p/old-post,/p/new-post
/2023/05/12/hello-world/,/p/hello-world
/about,https://example.com/about