File with an .FTL extension contains source text and a template stored in template language – FTL – definitions of variables and instructions for the FreeMaker program, used in order to generate new text. FTL files along with Java files or with some other programming language files generating a set of data, constitute an entry for the engine of FreeMaker, which than creates HTML pages, frameworks of Java classes or other source files in different languages.

FreeMaker can be built into Java software – it is an open source package, used for instance in the ECM Alfresco system. It can be used also for purpose of generating configuration files or email messages, It works on the basis of the MVC scheme (Model View Controller).