ReShell is a browser-based layout library, web desktop and user-interface (UI) services engine comprised of various open-source components from zenOSmosis and non-affiliated entities.

It is currently in an alpha phase, and other builds may have other built-in applications. These builds are called "portals".

ReShell is leveraged off of the source code for Speaker.app and other zenOSmosis projects based on PhantomCore, a library for managing the JavaScript application lifecycle.