Data file generated by CATALYST, a software localization program; stores translated files in a highly optimized database format capable of storing text or binary objects.

TTK files can be websites, online help systems, or software application files saved in an object-orientated database called a Project Translation Toolkit. They are composed of segments that each contain at least one source language string and its equivalent target language translation.

A TTK project can also be referred to as a "Translation Memory."