Rapla is described as 'flexible multi-user resource and event management system (Rooms, Groups, Students, Resources)' and is an app in the Office & Productivity category. There are five alternatives to Rapla for a variety of platforms, including Windows, Linux, Mac, Self-Hosted solutions and SaaS. The best alternative is Booked Scheduler. It's not free, so if you're looking for a free alternative, you could try Kairos Calendar. Other great apps like Rapla are Celcat Timetabler (Paid), Hub Planner (Paid) and ADE (Paid).
Booked (formerly phpScheduleIt) is a simple but powerful reserve-anything scheduler. With flexible layouts, custom rules, a powerful administrative backend, and an unbelievably simple user experience, Booked can fit almost any need.
A timetabling, resource planning and management solution aimed at schools, universities, corporations and military training centers. Written in Java JEE. Has a web interface, a desktop Java client, and an API.