Open source calendar projects
Every project in the registry tagged calendar, ranked by real GitHub adoption.
Goal-driven project management for all brains
Complete customer relationship management made simple
Modern TUI calendar and task manager with minimal and customizable UI.
Twake is a secure open source collaboration platform to improve organizational productivity.
Manage My Damn Life (MMDL) is a self-hosted frontend for managing your CalDAV tasks and calendars.
Invite others to grab times on your calendar. Choose a date. Make appointments as easy as it gets.
Related tags
Frequently asked questions
How many open source calendar projects are there?
This registry tracks 6 projects tagged calendar, with 20,438 GitHub stars between them. The most-adopted is Leantime at 11,597 stars.
Are these calendar projects free to use?
Yes — 6 of the 6 carry an explicit open-source licence across 4 distinct licences, so there is no licence fee. Where a project also sells a hosted or enterprise version, the self-hosted path remains free.
Which calendar project should I choose?
The list above is ranked by GitHub stars, but stars measure attention rather than fit. Check three things on each card: the licence (permissive versus copyleft), the language it is written in, and the last-push date — a high-star project that has not been pushed in a year is a liability.
Are these calendar projects still maintained?
5 of the 6 were pushed in the last 90 days, and every card shows its exact last-push date so you can see the rest. Sort your shortlist by that date before committing to a migration.