Open Source C# Email Software

Free Outlook Plugin, which synchronizes events, tasks and contacts between Outlook and Google, SOGo, NextCloud, Horde or any other CalDAV or CardDAV server. Supported Outlook versions are 2021, 2019, 2016, 2013, 2010 and 2007 and Office 365 for Desktop. This project was initially developed as a master thesis project at the University of Applied Sciences Technikum Wien, Software Engineering Degree program. Outlook CalDav Synchronizer is Free and Open-Source Software (FOSS), still you can support the project by donating on Sourceforge or directly within the About dialog of our Plugin. Contact us for enterprise support at https://caldavsynchronizer.org/enterprise/contact

A simple application to use Google calendar and email conveniently. It makes it easier to access Google services presenting them in a window in seperate tabs, also automating the logon by saving your user name (and password).

FreeMiCal allows the bulk export of MS Outlook appointment items to RFC 2445 conformant iCal format. .NET 2.0 or greater and Outlook 2003 or 2007 Interop Services required.

KReminder is outlook add-on, which sends reminders by email if they are not dismissed by user in specified amount of time. You can select different cell phone carriers such as T-Mobile, Sprint, Verizon and etc or regular email.

A mail/calendar/RSS client for Windows using the .NET 2.0 framework. Support POP, SMTP, GMail, GCalendar, iCal and local calendars. MyOE include and advanced spam filter, message sorting, live query, indexed search, and many more...

Nikita is a peer-to-peer PIM. It will offer all the same benefits of the standard PIMS (such as Outlook or Chandler) but will not require a central server. Items can be marked as Calendar, Task, Email, etc... or any combination of those. Silos be gone!

Teamworks is an opensource groupware built on top of JAVA/.NET web services backend with Mozilla XUL as the client UI

Toes Online is a person registration and management system which can be used by organisations to registrate members. It is a powerful tool with many features, including e-mailing, grouping and financial tools, with much focus on security and easy usage.