Kozea/Radicale

Baïkal is a Calendar+Contacts server

📇 Synchronize calendars and contacts.

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

☁️ Ultra-fast, secure & lightweight self-hosted cloud storage — your files, photos, calendars & contacts, all in one place. Built in Rust.

sabre/dav is a CalDAV, CardDAV and WebDAV framework for PHP

Meet the calendar that changes everything

☁️ Nextcloud server, a safe home for all your data

SOGo is a very fast and scalable modern collaboration suite (groupware). It offers calendaring, address book management, and a full-featured Webmail client along with resource sharing and permission handling. It also makes use of documented standards (IMAP, CalDAV, CardDAV, etc.) and thereby provides native connectivity (without plugins) to many clients such as Microsoft Outlook, Apple iCal, the iPhone, Mozilla Lightning, and a plethora of mobile devices.

All-in-one Mail & Collaboration server. Secure, scalable and fluent in every protocol (IMAP, JMAP, SMTP, CalDAV, CardDAV, WebDAV).