Interactive, iterative development of the entire OS

You can boot into a REPL (Read Evaluate Print Loop) and can inspect or rewrite any part of the OS as you are using it.

Dead simple and strong security

Whenever you run a program you tell it what it has access to, it doesn't get to choose. And every operation is type checked and bounds checked removing many common security vulnerabilities.

Command driven

Just like with emacs, even the GUI, desktop environment, or window manager can be controlled with commands and functions.


Find a critical bug with an OS function while writing your app? Just put your cursor over the buggy OS function or enter it into the console and your editor will jump you to the source code for it. Fix the function and viola, every program that uses that function instantly gets the fixed version, no need to even recompile or reload anything.


Insert a breakpoint or trace any part of the OS while using it. If an error occurs you can catch it, fix it, and restart execution to just before the error occurred.


Documentation is provided for the entire system in a first class fashion. (Meaning you can read and change the documentation in your programs.) Along with a comprehensive document explorer.

Fully Source Mapped

At runtime the user can view and modify the source of any component from the REPL, an editor, or in a program itself.

Symmetric Multi-Processing

3L is designed from the ground up to utilize multiple processors.


3L prioritizes user freedom. All code is released under the GPL.


Privacy by design. Combined with the security model is the power to choose exactly which information to make available to other programs. By default this is as minimual as possible.