Self-hosted
Xandikos is an Open-source CardDav and CalDav Server
What is Xandikos? Xandikos is a free open-source self-hosted CalDav and CardDav server that uses Git as a backend. It has been tested on a dozen of CalDav, and CardDav as well as vCard clients, which you will find in this post. Xandikos comes with a rich documentation for end-users,