At PAX East 2018, Square Enix announced that it will release the highly anticipated modding tools for Final Fantasy XV this Spring. Moreover, the team will add official Steam Workshop support on the Steam version so that modders can upload and share their creations easier.
Furthermore, Square Enix revealed that a Level Editor will also be available for the PC version of Final Fantasy XV. This Level Editor will allow players to create new quests, dungeons, chocobo races, vehicles and minigames. However, this Level Editor will not be released alongside the modding tools in Spring 2018. Instead, Square Enix plans to release it in Fall 2018.
Below you can find a video that shows the modding tools and the level editor in action.