Epic says it is 'vibe-coding' Unreal Engine 6 and Fortnite with AI tools

Epic Games is using AI coding tools across Unreal Engine and Fortnite, its executive vice president of development, Marcus Wassmer, said in a statement to This Week In Video Games, reported by PC Gamer and Polygon. "Yes, we are vibe-coding things," he said. "That means our engineers are no longer writing the bulk of the code, but they are still guiding the tools to get the architectural result we want."

Wassmer said almost all development is now happening in the work streams tied to Fortnite, Unreal Editor for Fortnite and Unreal Engine 6. PC Gamer reports he named Claude Code and Codex. He said the tools helped almost eliminate a type of cooking bug Epic had been fighting for a decade, and sped up a rewrite of part of the engine's D3D12 rendering layer.

"We are more concerned about the risks of moving too slowly than we are about AI skepticism," Wassmer said. Epic boss Tim Sweeney had already said on X that Epic uses AI tools to write code for Unreal Engine.