Refactoring, i.e., the process of changing a software system to improve its internal quality and preserving its external behavior, is gaining increasing acceptance among software developers. Even though many refactoring tools are now available for a variety of programming languages, most of them are difficult to reuse, extend or even customize, mainly because they provide no uniform way of representing and manipulating source code information. This paper presents a refactoring framework, called RefaX, which relies on open, XML-based source code models and processing standards to facilitate the development, customization and reuse of refactoring tools. In particular, RefaX makes it possible to develop refactoring tools that are independent of source code model, programming language and XML processing technology. The viability of the framework is illustrated through a refactoring prototype for Java.