Radicale
5.1kSimple calendar and contact server with extremely low administrative overhead.
SelfHostHub lists 10 open-source Calendar & Contacts projects you can host on your own server. The most-starred on GitHub are Radicale (5,125 stars), Baïkal (3,337 stars) and SabreDAV (1,727 stars). 3 of them document a Docker install.
Replacing a paid app? See open-source alternatives to Google Calendar.
Simple calendar and contact server with extremely low administrative overhead.
Lightweight CalDAV and CardDAV server based on sabre/dav.
Open source CardDAV, CalDAV, and WebDAV framework and server.
Calendar syncing tool that pulls and pushes events between calendar sources and destinations via iCal/ICS or OAuth, with support for anonymized busy/free events.
POP/IMAP/SMTP/Caldav/Carddav/LDAP exchange gateway allowing users to use any mail/calendar client with an Exchange server, even from the internet or behind a firewall through Outlook Web Access.
A simple, dockerizable and fully translatable admin interface for sabre/dav based on Symfony 5 and Bootstrap 4, largely inspired by Baïkal.
Manage my Damn Life (MMDL) is a self-hosted front end for managing your CalDAV tasks and calendars.
Open source CardDAV and CalDAV server with minimal administrative overhead, backed by a Git repository.
Day planner with drag-and-drop time blocking, inbox, recurring tasks, habits, routines, goals, projects and Pomodoro focus mode, plus iCal and CalDAV calendar sync. Data stays in the browser, with optional WebDAV or GLANCEvault sync.
Server for calendar sharing (CalDAV) that uses a PostgreSQL database as a data store.
By GitHub stars, the top projects in this category are Radicale (5,125 stars), Baïkal (3,337 stars) and SabreDAV (1,727 stars).
10 projects are currently listed in the Calendar & Contacts category on SelfHostHub.
The most common licences in this category are GPL-3.0 (4), MIT (3) and GPL-2.0 (2).
3 of the 10 projects list Docker as a supported platform. Check each project's documentation for the exact install steps.