The Template Toolkit (TT) is a template engine used primarily for building web sites, but is also suitable for creating any type of digital document, such as a PDF or LaTeX file.
It is written in Perl, with some popular accessories in C. It is released under a free software licence (Perl Artistic Licence or GPL).
The Template Toolkit was written by Andy Wardley.
The "prototype" for TT (the Text::MetaText Perl module) was released in 1996.
In the meantime, TT2 is steadily improved and has been released as version 3[2] late 2019.