Baïkal is a lightweight CalDAV and CardDAV server replacing Google Calendar sync with fast, private scheduling on SQLite or MySQL.
Google Calendar runs on corporate cloud infrastructure, pairing event storage with telemetry and continuous background scripts. Baïkal replaces that dependency with a lightweight CalDAV and CardDAV synchronization server for private hardware. By relying on a local database and standard web protocols, it synchronizes appointments across phones and desktops in milliseconds without consuming server capacity.
Google Calendar bundles calendar synchronization with a heavy cloud platform, pushing updates through memory-intensive web applications and background connections. In contrast, Baïkal prioritizes synchronization speed and minimal system overhead. Powered by sabre/dav and written in PHP, Baïkal handles calendar and contact queries using lightweight XML over HTTP. Paired with an SQLite or MySQL database, it answers synchronization requests in milliseconds while using only tens of megabytes of RAM. That low footprint ensures responsive synchronization on low-power hardware like a Raspberry Pi or entry-level virtual server.
The functional difference centers on the interface. Google Calendar and hosted services like Fastmail Calendar include browser views, natural-language event entry, and automated meeting invitations. Baïkal provides no end-user calendar interface—its web portal is strictly an administrative dashboard for provisioning accounts and address books. Users do not view schedules inside Baïkal; they connect native applications such as Apple Calendar on macOS and iOS, Thunderbird on Linux, or DAVx5 on Android. Transitioning requires exporting .ics archives and adding a CalDAV account to each device, after which synchronization runs natively without the lag of cloud web applications.
/.well-known/caldav redirection..ics feeds for unauthenticated web sharing without custom scripts.Can Baïkal replace Google Calendar for everyday scheduling? Baïkal replaces Google Calendar's storage and synchronization backend with private infrastructure. Users manage appointments through desktop and mobile apps rather than a web calendar interface.
Is Baïkal free for personal and commercial use? Yes, Baïkal is open-source software with no license fees or user seat restrictions.
Does Baïkal work with iPhones and Android devices? Yes, iOS connects natively via built-in CalDAV account settings, while Android synchronizes through standard helper apps like DAVx5.
Baïkal is an ideal choice for households seeking private calendar and contact synchronization without running a full groupware platform, provided they use native calendar applications instead of a browser portal. With active maintenance continuing through August 2026 and code governed by the GPL-3.0 terms, it provides a stable foundation for personal data sovereignty. Deploy it on a small server for lean protocol compliance, but choose an all-in-one platform like Nextcloud if you require an integrated webmail and calendar browser interface.
Free IDE for Java, Kotlin, Go, TypeScript and Python. Built on IntelliJ Community, fully open source, 300+ plugins.
Show that Baïkal is listed as an open-source alternative. Paste into your README: