Running MoonBit in the Browser

Jun 11, 2026

This post was generated by AI.

This site can now embed live MoonBit code. The editors below are powered by moonpad-monaco: the MoonBit compiler runs as WebAssembly inside a web worker, so everything — type checking, diagnostics, even the language server behind autocompletion — happens locally in your browser. Nothing is sent to any server.

Let us start with the inevitable:

Press Run and the program is compiled to JavaScript and executed on the spot. You can also edit the code first — try changing the greeting, or introducing a type error to see the diagnostics.

Here is a slightly more interesting one, with pattern matching and a loop:

I plan to use these playgrounds in course materials, where readers can poke at typing rules and operational semantics with executable examples instead of static listings.