Nextcloud is an open-source content collaboration platform providing file sync & share, groupware (calendar, contacts, mail), real-time office editing, chat and video conferencing.
36.6k stars5.1k forksAGPL-3.0last commit Actively maintained
17 self-hosted Apple iCloud Calendar alternatives
Apple iCloud Calendar is a cloud calendar service that syncs events, invitations, and shared calendars across iOS, macOS, and the iCloud web. It supports CalDAV for external clients, calendar sharing, notifications, and time zone handling.
Alternatives to Apple iCloud Calendar
#2
Lightweight CalDAV/CardDAV server for syncing calendars, to-dos, and contacts with many clients, storing data on the filesystem and supporting auth and TLS.
4.9k stars521 forksGPL-3.0last commit Actively maintained
#3
Baïkal is a lightweight CalDAV/CardDAV server with a web admin UI for managing users, calendars, and address books, backed by MySQL or SQLite.
3.3k stars317 forksGPL-3.0last commit Actively maintained
Prebuilt Nextcloud appliance and management tools for Raspberry Pi, Odroid, VMs and LXC; includes Apache, PHP, MariaDB, Redis, web panel and backup utilities.
2.9k stars320 forkslast commit Actively maintained
#5
Open source groupware suite providing webmail, calendaring, address books, and shared resources via open standards like IMAP, CalDAV, and CardDAV.
2.2k stars320 forksGPL-2.0last commit Actively maintained
#6
EteSync (Etebase Server) provides a self-hostable, zero-knowledge, end-to-end encrypted sync backend for calendars, contacts, tasks and notes across devices.
1.8k stars102 forksAGPL-3.0last commit Likely dormant
sabre/dav is a PHP framework for building WebDAV file servers and CalDAV/CardDAV calendar and contacts services.
1.7k stars369 forksBSD-3-Clauselast commit Actively maintained
Open-source task scheduler and calendar app that auto-plans tasks, syncs with external calendars, and provides a modern UI for managing time blocks and workflows.
985 stars70 forksMITlast commit Actively maintained
#9
Davis is a sabre/dav-based CalDAV/CardDAV/WebDAV server with a modern Symfony 7 admin dashboard for managing users, calendars, sharing, and address books.
743 stars46 forksMITlast commit Actively maintained
#10
Cyrus IMAP is a secure, scalable mail server providing IMAP/JMAP email plus CalDAV/CardDAV contacts and calendars, with ACLs, quotas, search, and replication.
643 stars175 forkslast commit Actively maintained
Self-hosted Next.js React CalDAV client for managing VTODO tasks and VEVENT calendars with multi-account, list/Gantt/calendar views and filters.
625 stars42 forksGPL-3.0last commit Actively maintained
#12
Lightweight CalDAV/CardDAV server implemented in Python that stores calendars and contacts in a Git-backed hierarchy with history and sync support.
597 stars57 forksGPL-3.0last commit Actively maintained
#13
Open-source, browser-based groupware providing calendar, email, file manager, CRM, projects, Collabora Online integration and SSO support.
295 stars113 forkslast commit Actively maintained
#14
PHP-based groupware and CRM for teams: calendars, contacts, email, file management, projects and CRM with CalDAV/CardDAV/IMAP support and extensible modules.
277 stars57 forksAGPL-3.0last commit Actively maintained
#15
Open-source PHP groupware providing CalDAV/CardDAV, ActiveSync, email client, CRM, tasks, file manager and Docker images for on-premise collaboration.
21 stars4 forksAGPL-3.0last commit Actively maintained
#16
DAViCal is an open source CalDAV/WebDAV calendar server using PostgreSQL, enabling shared calendars, access delegation, and meeting scheduling across many clients.
Activity unknown
#17
Citadel is an open source groupware and messaging server providing email, calendars, contacts, and a web interface with room-based collaboration.
Activity unknown
What replacing Apple iCloud Calendar actually involves
Every option on this page is open source and free to run on your own hardware, so you own the data and there is no subscription to cancel. 14 of 17 shipped a commit in the last six months. Licences in this list: AGPL-3.0, GPL-3.0, GPL-2.0, BSD-3-Clause, MIT. In exchange you take on hosting, backups and updates yourself.
Browse everything in Calendars & Contacts (CalDAV/CardDAV).
