It's designed to let a modder of any skill play around with the inner workings of the game, or perhaps even create your own entirely. The studio wants to arm gamers with amazing dev tools.
The dev kit lets you create all new environments, put together quests, flesh out character designs and even weave in your own branching storylines.
"For CD Projekt RED, RPGs are all about telling amazing stories. We want to give players the power to tell the same kind of non-linear, branching stories that made The Witcher games so popular," CD Projekt RED's Adam Badowski said.
"Our fans have helped us for years to make our games the best they can be, and REDkit is part of embracing our community as a partner in game development." Check out the to download the REDkit.