Baïkal
What Baïkal is
Baïkal is a free, open-source, self-hosted CalDAV and CardDAV server for calendars and contacts. Its web interface lets administrators manage users, address books, and calendars, while two-way synchronization connects compatible clients. Listed clients include iOS, Mac OS X, DAVx⁵ on Android, Mozilla Thunderbird, and other CalDAV- or CardDAV-capable applications. Baïkal stores data in MySQL, PostgreSQL, or SQLite and is powered by sabre/dav with an administrative interface added. Running it requires PHP, one of those database systems, and Apache or Nginx. Installation uses a release archive downloaded from GitHub, unpacked, and uploaded to the server. Guidance says only the html directory needs browser access and warns that the Specific directory may contain the SQL database; an Apache HTTPS virtual-host example is included. Docker instructions are marked unofficial. Before upgrading, the project advises backing up the database and Baïkal directory. The upgrade guide notes changed syncing endpoints for users moving from the former flat package. The linked releases page identifies version 0.12.1 as the latest release shown.
Who it suits
It suits people or organizations able to operate a PHP-based server and wanting self-hosted calendar and contact synchronization across compatible clients.
What it does well
- Free and open source under GNU GPL v3
- Supports two-way calendar synchronization
- Works with major CalDAV and CardDAV clients
- Stores data in three database options
- Provides a web administration interface
What to know first
- Requires self-hosting
- Needs PHP and Apache or Nginx
- Requires MySQL, PostgreSQL, or SQLite
- Docker instructions are unofficial
Plans
| Plan | Billed and limits | Price |
|---|---|---|
| Baïkal | Free and open-source · Self-hosted · Requires PHP, MySQL, PostgreSQL or SQLite, and Apache or Nginx | Free |
As sabre.io lists them, read 12 Oct 2026. The maker's own page has the final word.
Verdict
Baïkal provides self-hosted calendar and contact services with broad CalDAV and CardDAV client compatibility. Installation and upgrades require server administration, database management, and careful backups.
Facts from Baïkal's own pages
- Administration
- Its web interface manages users, address books and calendars. · sabre.io, 12 Oct 2026
- Calendar sync
- two_way · sabre.io, 22 Sept 2026
- Client compatibility
- The site lists compatibility with iOS, Mac OS X, DAVx⁵ on Android, Mozilla Thunderbird and other CalDAV/CardDAV-capable applications. · sabre.io, 12 Oct 2026
- Compatible clients
- The maker lists compatibility with iOS, Mac OS X, DAVx⁵ on Android, Mozilla Thunderbird, and other CalDAV- and CardDAV-capable applications. · sabre.io, 12 Oct 2026
- Databases
- It can store data in MySQL, PostgreSQL or SQLite. · sabre.io, 12 Oct 2026
- Deployment
- The installation guide directs users to download a release archive, unpack it, and upload it to their server. · sabre.io, 12 Oct 2026
- Docker
- The maker labels its Docker installation instructions unofficial. · sabre.io, 12 Oct 2026
- Download
- The installation guide directs users to download the latest release ZIP from GitHub and upload it to their server. · sabre.io, 12 Oct 2026
- Free plan
- Yes · sabre.io, 22 Sept 2026
- Hosting
- Baïkal is self-hosted and requires a PHP-capable server. · sabre.io, 12 Oct 2026
- HTTPS
- The installation guide includes an Apache HTTPS virtual host example with certificate and key file directives. · sabre.io, 12 Oct 2026
- Installation requirements
- Installation requires PHP, MySQL, PostgreSQL or SQLite, and Apache or Nginx. · sabre.io, 12 Oct 2026
- Latest release shown
- The linked GitHub releases page identifies version 0.12.1 as the latest release. · github.com, 12 Oct 2026
- License
- Baïkal is free and open-source under the GNU GPL v3 license. · sabre.io, 12 Oct 2026
- Maintenance note
- The upgrade guide says the former flat package is no longer available and syncing endpoints changed for users upgrading from it. · sabre.io, 12 Oct 2026
- Mobile apps
- ios and android · sabre.io, 22 Sept 2026
- Open source license
- Baïkal is free and open source under the GNU GPL v3 license. · sabre.io, 12 Oct 2026
- Purpose
- Baïkal is a lightweight CalDAV and CardDAV server for calendars and contacts. · sabre.io, 12 Oct 2026
- Security configuration
- The installation guide says only the html directory needs to be accessible from a browser and warns that the Specific directory may contain the SQL database. · sabre.io, 12 Oct 2026
- Security guidance
- The installation guide says only the html directory needs to be web-accessible and warns that Specific may contain the SQL database. · sabre.io, 12 Oct 2026
- Server requirements
- Installation requires PHP, MySQL, PostgreSQL or SQLite, and Apache or Nginx. · sabre.io, 12 Oct 2026
- Shared calendars
- Yes · sabre.io, 22 Sept 2026
- Storage
- It can store data in MySQL, PostgreSQL, or SQLite. · sabre.io, 12 Oct 2026
- Support
- The upgrade guide says users can contact the project for help with upgrade steps. · sabre.io, 12 Oct 2026
Where Baïkal stands on Freedom251
- Calendar apps#58 of 194