Which game engine powered Cyberpunk 2077 during its original development?

Cyberpunk 2077 was developed using REDengine 4. CD Projekt Red created and used this version of its proprietary technology for the game’s large open world, first-person presentation, vehicles, dialogue systems, and dynamic environments.

REDengine was developed by CD Projekt Red for its role-playing games. Earlier versions powered titles in The Witcher series, including The Witcher 2 and The Witcher 3. The Cyberpunk project required the engine to support firearms, driving, dense urban spaces, extensive verticality, and simultaneous cinematic and gameplay systems.

After Cyberpunk 2077 and its Phantom Liberty expansion, CD Projekt announced a move to Unreal Engine 5 for future projects. That later technology choice can cause confusion when people discuss the studio’s current development tools, but it does not change the engine used for Cyberpunk 2077.

REDengine 4 is the precise answer rather than the broader name REDengine. The number identifies the specific generation associated with the game’s original production.