Postiz-app vs Substack
Postiz-app and Substack are both marketing automation software. Postiz-app is open source under AGPL-3.0, with 41k GitHub stars. Substack is a commercial product from Substack Inc.
Which to pick
- Pick Postiz-app when
- You manage several social accounts and want a Buffer alternative you can self-host or buy hosted.
- Pick Substack when
- A writer wants to start a free or paid newsletter at no upfront cost and benefit from Substack's discovery network.
Side by side
A social media scheduler for planning, publishing and analysing posts across many networks, with team collaboration and AI assistance.
Newsletter and blog platform with paid subscriptions, podcasts, video and a reader network and app.
Each network needs its own developer app and API approval when self-hosting, and the app is AGPL licensed.
It takes 10 percent of paid subscription revenue, and branding and design control are limited.
Usable
Production-ready
Self-hosted server and cloud service
Cloud service and mobile app
TypeScript, NestJS, Next.js, Prisma and Redis
Not published
Open source, AGPL-3.0 (network copyleft)
Closed source, sold by Substack Inc.
Use inside your business is unrestricted. If you change it and let customers use it over the internet, you must publish your changes.
Closed source: you use it under the maker's terms and cannot change or resell the code.
41k GitHub stars
25k Wikipedia readers a month on phones
Established: started 3 years ago, latest release v2.25.3.
Not known
Other comparisons
More marketing automation platforms
Both sides were judged on 2026-11-03 from makers' descriptions, Wikipedia, READMEs and GitHub data. License, age and popularity lines are worked out directly.