Resource file used by programs developed with Microsoft's .NET Framework; stores objects and strings for a program in an XML format; may contain both plain text information as well as binary data, which is encoded as text within the XML tags.

RESX files are commonly used to store application settings and other program resources, such as pictures. If implemented correctly, they may be swapped out for other resource bundles without having to recompile the application again. This is useful when localizing programs to different environments. Even though RESX files may contain binary data, they still can be viewed with any text editor and parsed with a standard XML parser. Binary objects are encoded within <data> tags, which include properties for the program and MIME types. The application can decode the binary objects using the program type.