Radicale
Radicale is a small but powerful Privacy Tool CalDAV (calendars, to-do lists) and CardDAV (contacts) server, that:
- Shares calendars and contact lists through CalDAV, CardDAV and HTTP.
- Supports events, todos, journal entries and business cards.
- Works out-of-the-box, no complicated setup or configuration required.
- Offers flexible authentication options.
- Can limit access by authorization.
- Can secure connections with TLS.
- Works with many CalDAV and CardDAV clients.
- Stores all data on the file system in a simple folder structure.
- Can be extended with plugins.
- Is Open Source GPLv3-licensed free software.
I use it to self-host the synchronization of all my contacts and calendar events across all devices and clients:
- Mobile device contacts
- Desktop computers
- Self-hosted server
- Thunderbird email client
It's a work in progress and needs further configuration to be fully utilized across all devices.