Baikal — Lightweight Self-Hosted CalDAV and CardDAV Server

Introduction

Baikal is a self-hosted calendar and contact server that implements the CalDAV and CardDAV protocols. It provides a simple, standards-compliant backend so you can sync events, tasks, and address books across phones, desktops, and web clients without depending on Google or Apple cloud services.

What Baikal Does

• Serves CalDAV endpoints for calendar and task synchronization
• Serves CardDAV endpoints for contact synchronization
• Works with any standards-compliant client (iOS, Android, Thunderbird, GNOME)
• Manages multiple users and shared calendars via a web admin panel
• Stores data in SQLite or MySQL with minimal resource usage

Architecture Overview

Baikal is a PHP application built on the sabre/dav library, which is the reference implementation of WebDAV, CalDAV, and CardDAV in PHP. It runs on any web server that supports PHP (Apache, Nginx with PHP-FPM). Data is stored in SQLite by default or MySQL for multi-user deployments. The admin interface is a simple PHP web panel.

Self-Hosting & Configuration

• Deploy via Docker using community-maintained images or install on any LAMP/LEMP stack
• Run the web-based setup wizard on first launch to create the admin account
• Configure the database backend (SQLite or MySQL) during initial setup
• Place behind a reverse proxy with HTTPS for secure sync over the internet
• Set proper WebDAV rewrite rules in your web server configuration

Key Features

• Full CalDAV and CardDAV compliance tested with major clients and platforms
• Lightweight footprint suitable for single-board computers like Raspberry Pi
• Web-based admin panel for managing users, calendars, and address books
• Supports calendar sharing and delegation between users
• No JavaScript frameworks or complex build steps; plain PHP deployment

Comparison with Similar Tools

• Radicale — Python-based, file-backed; Baikal offers a web admin and SQL storage
• Nextcloud — full cloud suite with CalDAV built in; Baikal is far lighter if you only need calendars
• DAViCal — PostgreSQL-focused; Baikal is simpler to set up with SQLite
• Cyrus IMAP — includes CalDAV but is primarily a mail server; Baikal is calendar-only
• EteSync — encrypted sync; Baikal uses standard CalDAV without custom encryption

FAQ

Q: Which clients work with Baikal? A: iOS Calendar/Contacts, Android (DAVx5), Thunderbird, GNOME Calendar, Evolution, and any CalDAV/CardDAV client.

Q: Can multiple users share a calendar? A: Yes. The admin panel lets you create shared calendars and assign user permissions.

Q: Does Baikal support two-way sync? A: Yes. CalDAV and CardDAV are bidirectional protocols; changes sync both ways automatically.

Q: How do I back up Baikal data? A: Back up the Specific/ directory and the database file (SQLite) or run a MySQL dump.

Sources

• https://github.com/sabre-io/Baikal
• https://sabre.io/baikal/