The SpringCard Companion Service listen on TCP port 3998 and exposes an HTTP RESTful API to the clients.
Gives access to the SpringCard devices attached to the computer.
Gives access to all PC/SC readers (not only SpringCard's) attached to the computer.
Discovers devices that are available in the nearby, on network or BLE channels, and allow to attach them to the computer.
Retrieve SpringCard Companion Service's data, and allows to control it.