WebAssembly (WASM) is shipping in Chrome, Firefox, and Edge. Safari support is coming. For the first time, we can run compiled languages in the browser at near-native speed. This is a huge technical achievement, but the practical implications are still unclear.
What Is WebAssembly?
WebAssembly is a binary instruction format that browsers can execute. Write code in C, C++, or Rust, compile to .wasm, and run it in the browser. No plugins, no VMs—it's baked into the browser alongside JavaScript.
// Load and instantiate WebAssembly
fetch('module.wasm')
.then(response => response.arrayBuffer())
.then(bytes => WebAssembly.instantiate(bytes))
.then(results => {
const exports = results.instance.exports;
// Call WASM functions from JavaScript
const result = exports.add(5, 3);
console.log(result); // 8
});The performance wins are real. Benchmarks show 10-800x speedups over JavaScript for compute-heavy tasks. Parsing and compiling WASM is faster than JavaScript because the binary format is optimized for quick validation.