XLIFF is the XML Localization Interchange File Format designed by a group of multilingual content publishers, software providers, localization service providers, localization tools providers, and researchers. It is intended to give any multilingual content owner a single interchange file format that can be understood by any localization provider, using any conformant localization tool. While the primary focus is on being a lossless interchange format, usage of XLIFF as a processing format is neither encouraged nor discouraged or prohibited.

XLIFF Version 2.2. Part 2: Extended presents the XLIFF core as well as the optional modules that were created to store information about specific processes. For example, the Translation Candidates Module was designed to store translation suggestions and their associated metadata.