OpenCalendar Sync vs Claper
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?
OpenCalendar Sync
Self-hosted shared calendar with public event pages
VS
Claper
The ultimate tool to interact with your audience (alternative to
| Feature | OpenCalendar Sync | Claper |
|---|---|---|
| Category | Calendar & Contacts | Calendar & Contacts |
| License | MIT | GPL-3.0 |
| Language | TypeScript | Elixir |
| Setup difficulty | Medium | Medium |
| Min. RAM | 256 MB | 512 MB |
| Deployment | docker, source | docker |
| GitHub stars | ★ 852 | ★ 773 |
| First released | 2014 | 2026 |
| Replaces | Calendly, Google Calendar | — |
Why pick each one
Choose OpenCalendar Sync if…
- Released under the MIT license
- First-class Docker support for quick deployment
- Written in TypeScript
- Tiny footprint — runs in 256 MB RAM
Choose Claper if…
- Released under the GPL-3.0 license
- First-class Docker support for quick deployment
- Written in Elixir
- Lightweight — runs in 512 MB RAM
Frequently asked questions
Is OpenCalendar Sync or Claper better?
Neither is universally better. OpenCalendar Sync has the larger community; both share a medium setup difficulty, so the decision comes down to features and licensing.
Are OpenCalendar Sync and Claper free and open-source?
Yes. OpenCalendar Sync is licensed under MIT and Claper under GPL-3.0. Both can be self-hosted at no software cost.
Can I run OpenCalendar Sync and Claper with Docker?
OpenCalendar Sync: yes. Claper: yes.