Obsidian Entertainment is a US game developer headquartered in California. The company was founded in 2003 and has developed games like Alpha Protocol, Fallout: New Vegas and Dungeon Siege III. Obsidian game Pillars of Eternity, published by Paradox, is the result of a crowd-funding campaign using Kickstarter, which gave players the opportunity to invest in the project before it even existed. The game quickly rose as a favorite among critics and players, and qualifies as Paradox’ highest rated game from an external developer.

Colossal Order is a private Finnish game developer founded in 2009. The company has, among others, developed Cities: Skylines, which was released for PC in 2015 and based on IP belonging to Paradox. The game is one of Paradox’ most successful games to date.

Paradox currently has partnership agreements with a number of game studios around the world for yet unannounced games or porting of existing games to new platforms.

External partners in game development are used in addition to Paradox’ internal studios when they can contribute with additional capacity or specialist skills.