Best Open Source Calendar Software 2025

Calendar Software

Calendar Mac Office Suites BSD Clear Filters

Browse free open source Calendar software and projects for Mac and BSD below. Use the toggles on the left to filter open source Calendar software by OS, license, language, programming language, and project status.

Gen AI apps are built with MongoDB Atlas
The database for AI-powered applications.

MongoDB Atlas is the developer-friendly database used to build, scale, and run gen AI and LLM-powered apps—without needing a separate vector database. Atlas offers built-in vector search, global availability across 115+ regions, and flexible document modeling. Start building AI apps faster, all in one place.

Start Free
Simple, Secure Domain Registration
Get your domain at wholesale price. Cloudflare offers simple, secure registration with no markups, plus free DNS, CDN, and SSL integration.

Register or renew your domain and pay only what we pay. No markups, hidden fees, or surprise add-ons. Choose from over 400 TLDs (.com, .ai, .dev). Every domain is integrated with Cloudflare's industry-leading DNS, CDN, and free SSL to make your site faster and more secure. Simple, secure, at-cost domain registration.

Sign up for free
1

Group Office groupware and CRM

Take your office and CRM into the cloud!

Installation instructions can be found here: https://groupoffice.readthedocs.io/en/latest/install/install.html Group Office is an open source groupware application. It makes your daily office tasks easier. Share projects, calendars, files and e-mail online. It is a complete solution for all your online office needs. From a customer phone call to a project and finally an invoice. The support system helps to keep your customers happy. Group Office is fast, secure and has privacy by design. You can stay in full control of your data by self hosting your cloud and e-mail. Our document editing solution keeps all data on the secured server instead of synchronising it to all user devices. GroupOffice is open source and modular. Which means it’s easy to customise and extend. You can turn off and on features and it enables any developer to create new modules for the platform.

44 Reviews

Downloads: 69 This Week

Last Update: 1 day ago
See Project
2

EGG crm (Easy Graphical Genuine)

EGGcrm is an open source CRM web based. It provides reports with graphs, sales-management, e-mailing/webmail, data export, internal news, etc.. Online demo at www.eggcrm.net

Downloads: 0 This Week

Last Update: 2018-01-22
See Project
3

GoogleCalSugarCRM

Add events from SugarCrm (Meetings,Calls,Tasks) to an Google Calendar account ... with SMS alert enabled.

Downloads: 0 This Week

Last Update: 2013-04-03
See Project
4

PHPAdvocat

lawyer office suite

PHPAdvocat (Anwaltskanzlei-Suite) is a web based office suite for lawyer offices to manage contacts, files/documents, invoices and events. It is written in PHP and stores data in a PostgreSQL or MySQL database. Though it is mainly designed for german offices it should be adoptable for other countries. The Development has been moved to Gitlab: https://gitlab.com/phpadvocat/phpadvocat

1 Review

Downloads: 0 This Week

Last Update: 2022-08-29
See Project
Build Securely on Azure with Proven Frameworks
Lay a foundation for success with Tested Reference Architectures developed by Fortinet’s experts. Learn more in this white paper.

Moving to the cloud brings new challenges. How can you manage a larger attack surface while ensuring great network performance? Turn to Fortinet’s Tested Reference Architectures, blueprints for designing and securing cloud environments built by cybersecurity experts. Learn more and explore use cases in this white paper.

Download Now
5

Rendezvous Groupware Suite

Rendezvous is an open source web-based collaboration suite including e-mail, calendar, tasks, contacts, documents, projects, rss reader and mobile access. It features a rich user interface based on Adobe Flex.

Downloads: 0 This Week

Last Update: 2014-05-09
See Project