WebAssembly (Wasm)

WebAssembly (Wasm) is a compact binary instruction format that browsers can run at close to native speed, alongside JavaScript. Code written in languages such as C, C++, Rust and Go is compiled to a .wasm file and loaded by a web page.

It is used for performance-heavy work in the browser: games, video and image editing, CAD tools, emulators and running existing desktop libraries on the web. WebAssembly runs in the same secure sandbox as JavaScript and talks to the page through JavaScript. It also runs outside browsers, on servers and edge platforms, through WASI.