What is Baïkal used for?

Baïkal is a lightweight CalDAV and CardDAV server written in PHP for hosting your own calendars and contacts. It is a good fit for hosting family calendars and contacts at home, and replacing a cloud calendar provider.

Is Baïkal open source?

Yes. Baïkal is open source under the GPL-3.0 licence. Its source code is on GitHub at sabre-io/Baikal and is written mainly in PHP.

Yes. Baïkal is open source, so the software itself is free to use.

Can I self-host Baïkal?

Yes. Baïkal can be self-hosted on your own server or infrastructure; there is no official hosted version.

What is Baïkal an alternative to?

Baïkal is an open-source alternative to Google Calendar, Proton Calendar, Zoho Calendar and Apple Calendar. Other open-source alternatives to Google Calendar include Radicale, Manage My Damn Life and DAVx⁵.

Is Baïkal actively maintained?

Yes. The most recent commit to Baïkal was on 13 August 2026, and the latest release is 0.12.1, published on 5 August 2026. The project has 3.3k stars on GitHub.

Baïkal: open-source alternative to Google Calendar

About Baïkal

Baikal is a calendar and contacts server that implements the CalDAV and CardDAV protocols. It lets you host your own calendars and address books and sync them with clients that speak those standards. It is written in PHP, based on the sabre project, and licensed under GPL-3.0. The latest release listed is 0.12.1.

Installation, upgrading and troubleshooting information is on the sabre.io project page. The README also links two detailed community tutorials written for people with little IT experience: a German guide that sets up Baikal on a Raspberry Pi and covers Thunderbird, Android with DAVx5, sharing calendars, database maintenance and security, and a French guide covering installation on Debian and iOS clients.

Baikal was created by Jérôme Schneider of Net Gusto together with fruux and is now developed by volunteers. It suits individuals, families and small groups who want to keep calendars and contacts on their own server rather than with a large provider. Upgrade instructions are provided for moving between versions.

Key features

CalDAV calendar server
CardDAV contacts server
Written in PHP on the sabre library
Works with Thunderbird, DAVx5 and iOS
Upgrade instructions between versions

Good fit for

→Hosting family calendars and contacts at home
→Replacing a cloud calendar provider

Built with: PHP
Tags: caldav; carddav; calendar; contacts; php; self-hosted; sabre; sync

Baïkal: questions and answers

What is Baïkal used for?: Baïkal is a lightweight CalDAV and CardDAV server written in PHP for hosting your own calendars and contacts. It is a good fit for hosting family calendars and contacts at home, and replacing a cloud calendar provider.
Is Baïkal open source?: Yes. Baïkal is open source under the GPL-3.0 licence. Its source code is on GitHub at sabre-io/Baikal and is written mainly in PHP.
Is Baïkal free?: Yes. Baïkal is open source, so the software itself is free to use.
Can I self-host Baïkal?: Yes. Baïkal can be self-hosted on your own server or infrastructure; there is no official hosted version.
What is Baïkal an alternative to?: Baïkal is an open-source alternative to Google Calendar, Proton Calendar, Zoho Calendar and Apple Calendar. Other open-source alternatives to Google Calendar include Radicale, Manage My Damn Life and DAVx⁵.
Is Baïkal actively maintained?: Yes. The most recent commit to Baïkal was on 13 August 2026, and the latest release is 0.12.1, published on 5 August 2026. The project has 3.3k stars on GitHub.