hub.amSoftware by Xola
SOGo - SOGo is groupware server with a focus on scalability and open standards.
FareHarbor - Reservation software for activity and tourism businesses. Low credit card processing rates, mobile friendly. Built for you.
Baïkal - Cal and CardDAV server
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.
Xandikos - Lightweight CalDAV/CardDAV server on top of Git.
Checkfront - Checkfront is built for Tour & Activity Operators, Rental companies and Accommodation providers. Manage your inventories online, centralize reservations, process payments and get unified access to leading distribution channels.