Baïkal is an open source CalDAV and CardDAV server you can self-host — an iCloud and Google alternative that syncs your calendars and contacts across phones, laptops, and tablets, keeping them on your own server.

What is Baïkal?

Baïkal is a lightweight CalDAV and CardDAV server that lets you self-host your calendars and contacts. Built on the sabre/dav framework, it stores your appointments and address books on your own server and syncs them to any app that speaks the open CalDAV and CardDAV standards.

What is Baïkal best for?

Individuals, families, and small teams who want private calendar and contact sync without handing their schedule and address book to Apple or Google. It suits people comfortable running a small PHP app who prefer a simple web admin panel over editing config files by hand.

What can Baïkal do?

Serve calendars (CalDAV) and contacts (CardDAV) from a single server
Manage users, calendars, and address books through a built-in web admin interface
Sync with iOS, macOS, Mozilla Thunderbird, and DAVx5 on Android — any CalDAV/CardDAV client
Store data in SQLite for a zero-config setup, or MySQL/MariaDB for larger installs
Run on any basic PHP host with Apache or Nginx, or deploy via the official Docker image
Support .well-known auto-discovery so clients find the right endpoints
Share calendars and address books between users on the same server

Where does Baïkal fall short?

It’s a sync backend, not an app — there’s no web calendar or contacts view for daily use. The admin panel manages accounts; to actually see and edit events you need a separate client like Apple Calendar or Thunderbird.
It only does calendars and contacts. If you also want file sync, notes, photos, or a full collaboration suite, a broader platform like Nextcloud is a better fit.
Android has no native CalDAV/CardDAV support, so syncing there needs a third-party client such as DAVx5 — an extra app to install (paid on the Play Store, though free on F-Droid).

Is Baïkal free?

Yes — Baïkal is completely free and open source under the GPL-3.0 license. There’s no paid tier, no cloud edition, and no per-user cost; you only pay for the server or shared host you run it on. Because it’s lightweight PHP, that can be a cheap VPS or even basic shared hosting.

What does Baïkal replace?

Baïkal is a self-hosted alternative to the calendar and contact sync built into iCloud and Google Contacts, and to hosted CalDAV/CardDAV services like Fruux. It does the same cross-device sync job, but your calendars and contacts live on your own server instead of a provider’s cloud.

FAQ

Is Baïkal open source? Yes. Baïkal is licensed under GPL-3.0 and its full source is on GitHub. It’s built on the open sabre/dav framework and maintained by community volunteers.

Can I self-host Baïkal for free? Yes. The software is free; your only cost is the hosting. It runs on any basic PHP server with SQLite, so a low-cost VPS or shared host is enough.

Is Baïkal a good iCloud or Google alternative? For calendar and contact sync, yes — it works with the same Apple and standard clients and keeps your data private. It won’t replace iCloud’s file storage, photos, or device backup, which are separate features.

What do I need to run Baïkal? A web server (Apache or Nginx) with PHP, plus SQLite or MySQL/MariaDB for storage. There’s also an official Docker image if you’d rather not configure PHP by hand.