XLIFF (XML Localization Interchange File Format) is an XML-based format created to standardize the way localizable data are passed between tools during a localization process and a common format for CAT tool exchange. XLIFF was standardized by OASIS in 2002. Its current specification is v2.1 released on 2018-02-13, which is backwards compatible with v2.0 released on 2014-08-05. XLIFF is part of the Open Architecture for XML Authoring and Localization (OAXAL) reference architecture.