Open Source Scheduling and Calendar Apps

Your privacy-aware, open-source calendar with intuitive design and multi-platform syncing.

Evolution is a personal information management application that provides integrated mail, calendaring, address book and task list functionality.

Organize events with encrypted privacy, zero-knowledge and no tracking. Features include multi-device sync, multiple views, and offline support.

DAVx5 is a CalDAV/CardDAV management and sync app for Android.

Material design open source calendar for Android.

Web- and IMAP-based email service. 2GB cost 1€/month. Information is hosted on encrypted hard drives. Electricity from renewable resources is used.

WeekToDo is a free and Open Source minimalist weekly planner. With WeekToDo you can start improving your productivity by defining and managing your week and your tasks in an easy and intuitive way.

🎉 A beautiful Kotlin app to remember birthdays and events without having to open Facebook, set alarms or rely on Google Calendar.

Privacy-friendly Swiss email solution with 20 GB free storage, custom domain options, contact and calendar sync, and cross-device access in a secure suite.

Calendar interface for CalDAV, enabling cross-device event sync, web editing, recurring events, Nextcloud Contacts integration, WebCal support and attendee invites.

Right Calendar app is a versatile scheduling tool that offers unparalleled flexibility to its users. One of its standout features is that it is built on an open-source platform. This not only ensures transparency but also allows for constant updates and bug fixes from a...

All-in-one Open-Source productivity app and AI assistant with Tasks, Notes, Calendar, Diary and Bookmarks.

Nextcloud is the most deployed on-premises file share and collaboration platform. Access & collaborate across your devices. As fully on-premises solution, Nextcloud Hub provides the benefits of online collaboration without the compliance and security risks.

Itsycal is a tiny menu bar calendar. If you want, it will display your events as a companion to the Mac Calendar app.

fruux is a free service that takes care of your contacts, calendars and more so you don't have to. Never manually copy contacts and calenders between your devices again!

Merkuro is a calendar and contact application that allows you to manage your tasks, events and contacts. Merkuro supports both local calendars as well as a multitude of online calendars: Nextcloud, Google® Calendar, Outlook®, Caldav, and many more.

Personal Information Manager (Mail, Contact, Calendar and more).

Kolab provides a FOSS communication & collaboration solution that can be completely self-hosted. Take back control of your data and access it via the webinterface, or existing mobile & desktop clients.

An alternative mobile client for Untis Timetable, adding features such as filtering out certain classes.

Feature rich event, group and time managment system.

Comprehensive CalDAV and CardDAV server enabling local or remote calendar and contact access with configurable authentication.

MeetingBar is a menu bar app for your calendar meetings.

Calendar encryption: View calendars and stores them encrypted on your device or in the cloud.

Calcurse is a calendar and scheduling application for the command line. It helps keep track of events, appointments and everyday tasks. A configurable notification system reminds user of upcoming deadlines, the curses based interface can be customized to suit user needs and a...

BetterUntis is a features rich Untis Client for Android which has a modern and intuitive user interface.