OpenCalendar Sync vs vdirsyncer
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
vdirsyncer
Synchronize calendars and contacts via CalDAV/CardDAV
| Feature | OpenCalendar Sync | vdirsyncer |
|---|---|---|
| Category | Calendar & Contacts | Calendar & Contacts |
| License | MIT | BSD-3-Clause |
| Language | TypeScript | Python |
| Setup difficulty | Medium | Medium |
| Min. RAM | 256 MB | 64 MB |
| Deployment | docker, source | binary, source |
| GitHub stars | ★ 852 | ★ 1,859 |
| First released | 2014 | 2014 |
| Replaces | Calendly, Google Calendar | iCloud sync |
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 vdirsyncer if…
- Released under the BSD-3-Clause license
- Active community (1.9k GitHub stars)
- Written in Python
- Tiny footprint — runs in 64 MB RAM
Frequently asked questions
Is OpenCalendar Sync or vdirsyncer better?
Neither is universally better. vdirsyncer has the larger community; both share a medium setup difficulty, so the decision comes down to features and licensing.
Are OpenCalendar Sync and vdirsyncer free and open-source?
Yes. OpenCalendar Sync is licensed under MIT and vdirsyncer under BSD-3-Clause. Both can be self-hosted at no software cost.
Can I run OpenCalendar Sync and vdirsyncer with Docker?
OpenCalendar Sync: yes. vdirsyncer: check the project docs for container support.