Open source calendar projects
Every project in the registry tagged calendar, ranked by real GitHub adoption.
Goal-driven project management for all brains
Universal API for request permission and get its statuses.
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.
📅 A sleek and highly customizable calendar card for Home Assistant, designed for performance and a clean, modern look.
Atom Agent, Open-Source Governed AI Agent Platform for Self-Hosted Automation
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 9 projects tagged calendar, with 28,990 GitHub stars between them. The most-adopted is Leantime at 11,955 stars.
Are these calendar projects free to use?
Yes — 9 of the 9 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?
8 of the 9 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.