Services come in the two categories HTTP or WebSockets (well, and Fakes).
HTTP is used where classic requests make sense and no bidirectional communication is necessary. This applies, for example, to the API for adding or deleting locomotives, changing device settings or querying the current system status. The following endpoints are defined for HTTP.
WebSockets are used where fast bidirectional data communication is necessary. This primarily affects all the different APIs for firmware and sound updates, e.g. DECUP or ZUSI, but also the Z21 endpoint. The following endpoints are defined for WebSockets.