A development environment develops a data transfer interface, which converts message traffic between a first data system and a second data system. The systems have a first and a second data structure respectively. The development environment consists of two structure modelers, one for each data system, and a matcher. The first structure modeler provides a model of the first data structure. The model is developed for each message type of a predetermined group of message types. The first structure modeler input consists of at least one sample message of each of the message types. The second structure modeler develops, from second system responses to test data, a second data structure model for each of the message types. The matcher supports matching of elements of the first structure model to corresponding elements of the second structure model, thereby forming a message type mapping.