Top 6 Calendar and Address Book Open-Source Projects

Radicale

31 3,104 9.3 Python

A simple CalDAV (calendar) and CardDAV (contact) server.

Project mention: Stalwart All-in-One Mail Server (IMAP, JMAP, SMTP) | news.ycombinator.com | 2023-07-18

Maybe https://radicale.org/ could fit the bill, CalDav for as a calendar server and CardDav for contacts.

Baïkal

37 2,340 6.8 PHP

Baïkal is a Calendar+Contacts server

Project mention: I have a cloud storage problem! | /r/selfhosted | 2023-12-07

InfluxDB

www.influxdata.com sponsored

Power Real-Time Data Analytics at Scale. Get real-time insights from all types of time series data with InfluxDB. Ingest, query, and analyze billions of data points in real-time with unbounded cardinality.
sabre/dav

11 1,465 8.1 PHP

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

Project mention: My email host doesn’t provide calendar services. How can I run my own and send meeting invites? | /r/selfhosted | 2023-06-06

https://sabre.io/ is an option.

AgenDAV

8 632 0.0 JavaScript

A CalDAV web client similar to Google Calendar

Project mention: Projects ideas | /r/learnprogramming | 2023-07-12

I ended up using agendav but its quite limited and adding people to calendars is a bit janky.

ownCloud calendar

0 121 6.4 JavaScript

Calendar app for ownCloud (by owncloud)
CalendarServer

0 12 0.0 Python

mirror http://svn.calendarserver.org/repository/calendarserver/CalendarServer/trunk

NOTE: The open source projects on this list are ordered by number of github stars. The number of mentions indicates repo mentiontions in the last 12 Months or since we started tracking (Dec 2020).