{{stub}}{{language|site=https://onyxlang.io/}}
Onyx is a WebAssembly-first language (`app.wasm`). WebAssembly can be used inside of a browser but is also growing in popularity outside of the browser, in part due to projects like Wasmer, Wasmtime, and WasmEdge. These "controlled environments" could be game engines, where WASM is used as a "script" system; cloud functions, where WASM is used to respond to requests; plug-in systems for editors or tools.

Onyx uses a modernized C-like syntax, similar to Jai or Odin. Onyx is an imperative and procedural language in which statements are evaluated in the order they are written in, but does allow for functional-inspired syntax using the pipe operator.

For example:

<syntaxhighlight lang="C">
use core { printf, iter }

main :: () {
    for i in 1 .. 10 {
        fact := factorial(i);
        printf("{}! = {}\n", i, fact);
    }
}

factorial :: (n: i32) -> i32 {
    return iter.as_iter(1 .. n)
        |> iter.fold(1, (x, y) => x * y);
}
</syntaxhighlight>