Radicale is a minimal CalDAV and CardDAV server you run on your own hardware or VPS. It stores calendar events and contacts locally in standard iCalendar and vCard files, and works with any standards-compliant client: DAVx5 on Android, Apple Calendar, Thunderbird, and others. Setup is a single Python package with no external database required.
Radicale
radicale.org
Our take
If you want your calendars and contacts off Google’s and Apple’s servers with the least possible complexity, Radicale is the most direct path. The configuration is minimal, the file format is portable, and the GPLv3 codebase has been maintained since 2008. The catch is that self-hosting a CalDAV server adds operational overhead: you need a server, TLS, and ideally backups, before it is reliable enough to replace a managed service. Privacy from self-hosting is real and meaningful, but it is not end-to-end encryption. Pair it with DAVx5 on Android and a CalDAV client on desktop, and it replaces Google Calendar without leaving a copy of your schedule on any third-party server.
GitHub at a glance
Kozea/Radicale
Stars
4,763
Last commit
today
healthy
License
GPL-3.0
Latest release
v3.7.5
8d ago
Listed in
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Radicale license, in plain English
GPL-3.0 Strong copyleft
Free to use and modify, but anything you distribute that is built on it must also be open under the same license.
Permits
- Commercial use
- Modification
- Distribution
- Patent use
- Private use
Requires
- Disclose source
- Same license
- State changes
- License and copyright notice
Does not provide
- Liability cover
- Warranty
Why it matters: Strong copyleft keeps every distributed version open. A vendor cannot fold this into a closed product and ship it without releasing their changes.
Plain-language summary of the project's license, not legal advice. Read the full text for the exact terms.