Radicale : The Radicale Project is a complete CalDAV (calendar) and CardDAV (contact) server solution.
deepstream.io : A Scalable Server for Realtime Web Apps
Stores and syncs data in realtime
Built in node.js
Works for browsers, backend & mobile
Scales via clustering...
RoadRunner : RoadRunner is an open source (MIT licensed), high-performance PSR-7 PHP application server, load balancer and process manager. It supports service mod...
Rocketeer : The fast deployer for modern applications
Iron : Iron is a fast and flexible middleware-oriented server framework that provides a small but robust foundation for creating complex applications and RES...
Baïkal offers ubiquitous and synchronized access to your calendars and address books over CalDAV and CardDAV. Baïkal implements the current IETF recommendation drafts of these industry standards for centralized calendar and address book collections.