Try Luma in your browser
Edit the code and press Run. The real Luma compiler runs inside this page on your own device, so nothing you type is sent to a server. The first run downloads the engine once (a few megabytes); after that it works offline.
Not available here: Python and native packages, files, databases, network requests, secrets and keyboard input. Games, desktop apps and servers open windows or ports, so run those with the luma command on your computer. Website code is previewed in a sandboxed frame.