ClearFlask 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?
ClearFlask
Community-feedback tool for managing incoming feedback and
VS
Open Event Server
Self-hosted event management and ticketing backend
| Feature | ClearFlask | Open Event Server |
|---|---|---|
| Category | Calendar & Contacts | Calendar & Contacts |
| License | AGPL-3.0 | GPL-3.0 |
| Language | Java | Python |
| Setup difficulty | Medium | Hard |
| Min. RAM | 512 MB | 1,024 MB |
| Deployment | docker | docker, source |
| GitHub stars | ★ 446 | ★ 3,006 |
| First released | 2025 | 2016 |
| Replaces | — | Eventbrite, Sched |
Why pick each one
Choose ClearFlask if…
- Released under the AGPL-3.0 license
- First-class Docker support for quick deployment
- Written in Java
- 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 ClearFlask or Open Event Server better?
Neither is universally better. Open Event Server has the larger community, while ClearFlask is simpler to set up (medium difficulty). Choose based on the comparison table above and your own setup.
Are ClearFlask and Open Event Server free and open-source?
Yes. ClearFlask is licensed under AGPL-3.0 and Open Event Server under GPL-3.0. Both can be self-hosted at no software cost.
Can I run ClearFlask and Open Event Server with Docker?
ClearFlask: yes. Open Event Server: yes.