Mapping of a first native data type instance to a second native data type instance is performed in three stages: the first native data type instance is converted into a first programming language and platform independent representation conforming to a first schema capable of defining base and derived data types; the first programming language and platform independent representation is transformed into a second programming language and platform independent representation conforming to a second schema capable of defining base and derived data types; and the second programming language and platform independent representation is converted into the second native data type instance. The programming language and platform independent representations may be event-based extensible Markup Language (XML) representations implemented according to the Simple API for XML (SAX). The transformation may be governed by an extensible Stylesheet Language Transform (XSLT) stylesheet.