Baïkal - Cal and CardDAV server
Travolutionary - Travolutionary is an aggregation, reservation and distribution platform by Gimmonix, with access to hundreds of travel inventory providers across hotel, air, car and content.
Radicale - The Radicale Project is a complete CalDAV (calendar) and CardDAV (contact) server solution.
Eventric - Eventric is an professional tour management solution.
SOGo - SOGo is groupware server with a focus on scalability and open standards.
Rezdy - Tour operators in 73 countries use Rezdy's booking software to sell thousands of products in real-time on their website and through distribution channels.