WebAssembly (wasm) is a high-performance assembly-like format optimized for the web. Code targeting WebAssembly can run at near-native speeds while still benefiting from the safe environment of a browser VM. Wasm has opened up a whole new world of demanding desktop-class apps that can comfortably run in the browser. For example, AutoCAD was able to port decades of code to the web using wasm. Cases like AutoCAD’s have made it clear that wasm will be a major disruptive force in how web apps are developed.

To facilitate the adoption of wasm, WebAssembly team developed a powerful compiler toolchain library called binaryen. Binaryen does a huge amount of heavy lifting for compiler authors. It offers dead code removal, code size reduction, and various performance optimizations out of the box.