1. A computer-based method comprising: exchanging, by a first transaction-tax-related application executed by a computer, transaction-related data with at least a second transaction-tax-related application according to a standardized transaction-tax interface data model, wherein the first transaction-tax-related application uses a first application-specific data model; and mapping, by the computer, between data elements of the first application-specific data model and corresponding data elements of the standardized transaction-tax interface data model, wherein the standardized transaction-tax interface data model is defined so as to provide data elements at least for a first jurisdiction and a second jurisdiction, wherein the standardized transaction-tax interface data model has at least one first data element which is used for transaction tax calculation in the first jurisdiction, but is not used for transaction tax calculation in the second jurisdiction, and at least one second data element which is used for transaction tax calculation in the second jurisdiction, but is not used for transaction tax calculation in the first jurisdiction.