This method can be used to sign different types of receipts according to local fiscalization regulations. After signing the receipt according to the fiscal law, this method asynchronously returns the data that need to be printed onto the receipt. The format of the receipt request is documented in the Middleware API docs, and the exact behavior of the method is determined by the cases sent within the properties (e.g. ftReceiptCase, ftChargeItemCase and ftPayItemCase.

This method can be used to verify that the communication to the POS API and the underlying Middleware are working without any side effects.

This method can be used to "print" a digital receipt, based on the receipt-request and -response pair from signing a receipt via the sign endpoint. The asynchronously created response contains the link to the digital receipt.

For further information about the digital receipt, please refer to the Middleware API documentation

This method can be used to trigger a digital payment via one of the payment providers supported by the Middleware (details coming soon). The request is processed asynchronously, as payment operations may take a while, depending on the provider.

Payment operations will be identified by the used `ftPayItemCase` (e.g. cash payments won't trigger any online payment operations); currently this method triggers on credit- and debit card cases.

The payment provider and the required credentials will be configurable in the Portal and connectable to the used Middleware instance soon.

This method is used to obtain the result of a previously executed asynchronous operation. Callers should pass the result object from this referenced operation into the body, and the method will either return the requested response, or HTTP 204 in case the operation has not finished yet.