Currently no central exception handling is applied. Most exceptions either go to the logs or are thrown over the web framework boundaries so that they are directly reported to the client. A central exception handler should be added which differentiates between recoverable and non-recoverable exceptions. In case of non-recoverable exceptions the transaction should be rolled-back and a proper message should be reported to the user. In case of recoverable exceptions it should differentiate between exceptions which require user input in order to retry an operation or if it can be solved on the server-side.