Abstract: In order to use object-oriented models over the Internet for applications in different type systems it is necessary to marshal and unmarshal objects between Java, SQL and XML. Hand-writing specific code to do this is difficult. A computer-implemented method of generating serialization code for representing a model in a plurality of type systems is disclosed, the method comprising the steps of: i) producing an input file from the model for a given set of objects; and ii) providing a code generator for acting on the input file to generate the serialization code.