What is the name of Roblox's game development environment?

Roblox's game development environment is called Roblox Studio.

Roblox Studio is the software and game engine used to create experiences for the Roblox platform. It provides tools for building three-dimensional worlds, designing gameplay, importing assets, testing projects, and publishing them for other users. Studio was made available alongside Roblox's 2006 public release.

Roblox Studio is closely tied to the platform's user-generated-content model: the company supplies the underlying engine and services, while creators build the individual games and experiences. Its scripting system uses Luau, a Roblox-developed dialect of Lua 5.1. This makes Roblox Studio different from Unity, Unreal Engine, and GameMaker, which are general-purpose development tools used across many platforms. Roblox games may look as varied as traditional video games, but they are created within Roblox Studio and run through Roblox's platform.