Looks promising

The biggest advantage of Hydra over its competitors is that it keeps the appointment creation process simple and understandable. It seems to have been designed by an engineer for humans. In other appointment systems, the appointment creation process is complicated and difficult to understand. Hydra makes this process as simple as 1-2-3. Its second advantage is its wide integration support. Many integration options are available in Hydra and more are on the way. Of course, it has its shortcomings at the moment, but it will be a strong alternative in the future.