Wikipedia
Transifex is a proprietary, web-based translation platform; that is to say, it is a globalization management system (GMS). It targets technical projects with frequently updated content, such as software, documentation and websites and encourages the automation of the localization workflow by integrating with the tools used by developers.
Transifex is provided as software as a service (SaaS). It features paid plans, as well as a gratis (free of charge) plan for localizing open source software. Transifex itself was originally an open source project, but the development of an open source version of the software was discontinued in 2013. Hence, any further improvement of Transifex is only available to users of the proprietary Transifex SaaS.