Alf.io vs OpenSlides
A side-by-side comparison of two self-hosted calendar & contacts options — licensing, setup difficulty, resource needs, and what each one replaces.
Not the right match-up?
Alf.io
Ticket reservation system
VS
OpenSlides
Presentation and assembly system for managing and projecting agenda,
| Feature | Alf.io | OpenSlides |
|---|---|---|
| Category | Calendar & Contacts | Calendar & Contacts |
| License | GPL-3.0 | MIT |
| Language | Java | Shell |
| Setup difficulty | Medium | Medium |
| Min. RAM | 512 MB | 512 MB |
| Deployment | bare-metal | docker |
| GitHub stars | ★ 1,601 | ★ 629 |
| First released | 2025 | 2026 |
| Replaces | — | — |
Why pick each one
Choose Alf.io if…
- Released under the GPL-3.0 license
- Active community (1.6k GitHub stars)
- Written in Java
- Lightweight — runs in 512 MB RAM
Choose OpenSlides if…
- Released under the MIT license
- First-class Docker support for quick deployment
- Written in Shell
- Lightweight — runs in 512 MB RAM
Frequently asked questions
Is Alf.io or OpenSlides better?
Neither is universally better. Alf.io has the larger community; both share a medium setup difficulty, so the decision comes down to features and licensing.
Are Alf.io and OpenSlides free and open-source?
Yes. Alf.io is licensed under GPL-3.0 and OpenSlides under MIT. Both can be self-hosted at no software cost.
Can I run Alf.io and OpenSlides with Docker?
Alf.io: check the project docs for container support. OpenSlides: yes.