Top CALENDAR GitHub Repositories & Tools (2026)

Built from the ground up for speed. Flectar Mail delivers native performance, instant startup, and as little as 20 MB of RAM.

Self-hosted family planner - tasks, calendars, shopping, meals, budget. Your data, your server.

Leantime is a goals focused project management system for non-project managers. Building with ADHD, Autism, and dyslexia in mind.

:date: Easy!Appointments - Self Hosted Appointment Scheduler

EspoCRM – Open Source CRM Application

DAVx⁵ is an open-source CalDAV/CardDAV suite and sync app for Android. You can also access your online files (WebDAV) with it.

Menu bar calendar for macOS - MVVM | RxSwift | AppKit | SwiftUI

Sync your Outlook and Google calendars

Query and format a set of opening hours

Easily access public holidays for 200+ countries via .NET, REST API, Docker, or NuGet for online and offline use.

📆 Calendar app for Nextcloud

iCal-creator for PHP

📅 Calendar link generator for popular services

Parser for iCalendar Events • PHP 8+, 7 (≥ 7.4), 5 (≥ 5.6)

A modern, open-source Full Calendar alternative for React. Month, week, day, and year views with drag-and-drop, horizontal and vertical resource views, and RFC 5545 recurring events — all MIT licensed.

📆 Event and occurrence scheduling application for Django

Group Office groupware and CRM

DNTPersianUtils.Core is a collection of Persian helper extension methods

A beautiful, custom Home Assistant calendar card

A perpetual Jewish Calendar