Radicale Simple calendar and contact server with extremely low administrative overhead. Self-hostedOpen sourceCalendar & Contacts 5,151GPL-3.0Pythonupdated Oct 2026
Baïkal Lightweight CalDAV and CardDAV server based on sabre/dav. Self-hostedOpen sourceCalendar & Contacts 3,349GPL-3.0PHPupdated Oct 2026
S SabreDAV Open source CardDAV, CalDAV, and WebDAV framework and server. Self-hostedOpen sourceCalendar & Contacts 1,727MITPHPupdated Oct 2026
K Keeper.sh 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. Self-hostedOpen sourceCalendar & Contacts 1,425AGPL-3.0Dockerupdated Oct 2026
D DavMail 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. Self-hostedOpen sourceCommunication - Email - Mail Delivery AgentsCalendar & Contacts 774GPL-2.0Javaupdated Oct 2026
Davis A simple, dockerizable and fully translatable admin interface for sabre/dav based on Symfony 5 and Bootstrap 4, largely inspired by Baïkal. Self-hostedOpen sourceCalendar & Contacts 761MITPHPupdated Oct 2026
Manage My Damn Life Manage my Damn Life (MMDL) is a self-hosted front end for managing your CalDAV tasks and calendars. Self-hostedOpen sourceCalendar & Contacts 644GPL-3.0Nodejsupdated Sept 2026
X Xandikos Open source CardDAV and CalDAV server with minimal administrative overhead, backed by a Git repository. Self-hostedOpen sourceCalendar & Contacts 612GPL-3.0Pythonupdated Oct 2026
D dayGLANCE 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. Self-hostedOpen sourceTask Management & To-do ListsCalendar & Contacts 178MITJavascriptupdated Oct 2026
DAViCal Server for calendar sharing (CalDAV) that uses a PostgreSQL database as a data store. Self-hostedOpen sourceCalendar & Contacts 112GPL-2.0PHPupdated May 2026