XMI (XML Metadata Interchange) is an OMG standard for exchanging metadata information via XML. It can be used for any metadata whose metamodel can be expressed in MOF. The most common use of XMI is as an interchange format for UML, although it can also be used for other purposes.
XMI is difficult to implement correctly and lacks many features required for real-world use such as the relative placement of items in the diagrams. Unfortunately this means exchanging files between UML diagramming programs using XMI is rarely possible.
