Hydra is a service that accepts connections from incoming clients and makes these clients available to a virtual midi port interface.

For example, you could have some music track playing from a midi sequencer program such as ableton, and have these clients be able to control some midi instrument as determined by whatever you have programmed in the sequencer.

It keeps a list of all connected clients. Communications are 2 way between the midi ports and client. The system will arbitrarily choose one of the clients to control the midi instrument if

There is also the HydraHead android app that works in conjuntion with the service. The app allows for auto connecting to some wireless access point so there is no configuration needed for client users to connect to the performance.