Open source · AGPL-3.0 · Built on Cloudflare
FlockStack is an open-source newsletter platform, an alternative to beehiiv and Substack. Write an issue, send it to your list and publish it on your own domain. You pay for the emails you send, not for dormant subscribers.
How it works
Draft it in the editor, add your images, then send it now or schedule it for later.
Import your subscribers from a CSV, or collect them with a signup form. Welcome emails and double opt-in are built in.
Every issue lands in an archive on your own domain, next to a signup form for new readers.
Features
No tiers to unlock. A bigger plan sends more emails, nothing else changes.
Campaigns and scheduling
Write an issue, send it now or schedule it.
Welcome emails
A first email for every new subscriber.
Double opt-in
Subscribers confirm their address before they join.
CSV imports
Bring your list from beehiiv, Substack, Mailchimp, Kit and others.
Open and click stats
See how every issue did.
A website with an archive
Your issues live on a public site of their own.
Signup forms
Collect subscribers on your site, or anywhere else.
Custom domain
Serve your site from your own domain.
No “Powered by” badge
Your newsletter carries your name, not ours.
Warm-up sending
Big sends go out gradually while your sending reputation builds.
List cleanup
Readers who stop opening get one last chance, then stop receiving issues. Nobody is deleted.
Bounce and complaint limits
A campaign pauses when bounces or spam complaints climb too high.
One-click unsubscribe
Readers can leave in one click, right from their mail app.
REST API
Everything the dashboard does, from your own code.
MCP server
Let ChatGPT, Claude, Cursor or Codex run your newsletter, under the same checks as the dashboard.
Passkey sign-in
Sign in with your device. No password to leak.
Pricing
Pick the emails you send in a month. Yearly plans cost 10 months instead of 12.
75,000
For up to 40,000 subscribers
Growth
$0.36 per 1,000 emails
$27/month
Billed monthly
Every plan includes
Create your account and set up your newsletter first.
Sending more than 2,000,000 emails a month? Email hello@flockstack.io
Compared
MailCheap publishes prices for the same five email volumes. Monthly prices side by side, checked October 2026.
| Emails a month | FlockStack | MailCheap | You save |
|---|---|---|---|
| 20,000 | $12 | $19 | $7 (37%) |
| 75,000 | $27 | $39 | $12 (31%) |
| 200,000 | $55 | $79 | $24 (30%) |
| 500,000 | $109 | $149 | $40 (27%) |
| 2,000,000 | $299 | $349 | $50 (14%) |
Prices only: what a plan includes differs between the two. MailCheap's are from its pricing page at mailcheap.ai, as of October 2026.
Questions
Yes. FlockStack is licensed under the AGPL-3.0: you can read the code, change it and run it on your own server.
FlockStack Cloud, at flockstack.io, runs the same code for people who would rather not host it.
On Cloudflare, in the region you pick when you sign up: the United States or the European Union. Your newsletters, subscribers and campaigns are stored in D1, and your images in R2, in that region. An account lives in one region. The docs list where each kind of data is stored.
Yes. Export your subscribers as a CSV from beehiiv, Substack, Mailchimp, Kit or another platform, and import the file. The exports work as they are.
Campaigns and welcome emails pause until you upgrade or the next month starts. Signups keep working, and confirmation emails still go out. Nothing is billed on top of your plan.
Each plan also sets how many subscribers you can hold, shown next to its emails in the slider above.
Yes. Everything the dashboard does is also in the REST API and in an MCP server, so ChatGPT, Claude, Cursor or Codex can write, schedule and send for you, under the same checks and limits as a person.
Create your account, import your list and write your first issue.