OpenCalendar Sync vs EteSync
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
EteSync
End-to-end encrypted sync for contacts and calendars
| Feature | OpenCalendar Sync | EteSync |
|---|---|---|
| Category | Calendar & Contacts | Calendar & Contacts |
| License | MIT | AGPL-3.0 |
| Language | TypeScript | Python |
| Setup difficulty | Medium | Medium |
| Min. RAM | 256 MB | 256 MB |
| Deployment | docker, source | docker, bare-metal |
| GitHub stars | ★ 852 | ★ 1,765 |
| First released | 2014 | 2017 |
| Replaces | Calendly, Google Calendar | Google Calendar, iCloud |
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 EteSync if…
- Released under the AGPL-3.0 license
- First-class Docker support for quick deployment
- Active community (1.8k GitHub stars)
- Written in Python
Frequently asked questions
Is OpenCalendar Sync or EteSync better?
Neither is universally better. EteSync has the larger community; both share a medium setup difficulty, so the decision comes down to features and licensing.
Are OpenCalendar Sync and EteSync free and open-source?
Yes. OpenCalendar Sync is licensed under MIT and EteSync under AGPL-3.0. Both can be self-hosted at no software cost.
Can I run OpenCalendar Sync and EteSync with Docker?
OpenCalendar Sync: yes. EteSync: yes.