Cal.diy vs Open Event Server
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?
Cal.diy
Online appointment scheduling system
VS
Open Event Server
Self-hosted event management and ticketing backend
| Feature | Cal.diy | Open Event Server |
|---|---|---|
| Category | Calendar & Contacts | Calendar & Contacts |
| License | MIT | GPL-3.0 |
| Language | TypeScript | Python |
| Setup difficulty | Medium | Hard |
| Min. RAM | 512 MB | 1,024 MB |
| Deployment | bare-metal | docker, source |
| GitHub stars | ★ 47,334 | ★ 3,006 |
| First released | 2026 | 2016 |
| Replaces | — | Eventbrite, Sched |
Why pick each one
Choose Cal.diy if…
- Released under the MIT license
- Mature project with 47.3k GitHub stars
- Written in TypeScript
- Lightweight — runs in 512 MB RAM
Choose Open Event Server if…
- Released under the GPL-3.0 license
- First-class Docker support for quick deployment
- Active community (3k GitHub stars)
- Written in Python
Frequently asked questions
Is Cal.diy or Open Event Server better?
Cal.diy is the stronger all-round pick: it has both the larger community and the simpler medium setup. Consider Open Event Server if its specific feature set fits your needs better.
Are Cal.diy and Open Event Server free and open-source?
Yes. Cal.diy is licensed under MIT and Open Event Server under GPL-3.0. Both can be self-hosted at no software cost.
Can I run Cal.diy and Open Event Server with Docker?
Cal.diy: check the project docs for container support. Open Event Server: yes.