TMX (Translation Memory eXchange) is an open XML standard for the exchange of translation memory data created by CAT (computer-aided translation) and localisation tools. Being in existence since 1998, the format allows easier exchange of translation memory between tools and/or translators with little or no loss of critical data. TMX forms part of the Open Architecture for XML Authoring and Localization (OAXAL) reference architecture. See the Wikipedia article on TMX.