World of Warcraft Game Engine: Custom "WoW Engine"

World of Warcraft runs on a proprietary, custom-built engine internally called the "WoW engine" (or "the engine").

• Not Unreal, Unity, CryEngine, or any third-party tech.
• Developed in-house by Blizzard since 1999; continuously rewritten (rendering, networking, scripting, UI, audio).
• Lua scripting layer: UI and encounter logic exposed via Lua API for addons.
• Cross-platform: Windows, macOS (Metal), with shared asset pipeline.

Its longevity stems from modular architecture allowing 20+ years of graphical overhauls (DX11→DX12, ray tracing, DLSS) without full rewrites.