## What is WebAssembly?
WebAssembly (WASM) is a low-level binary format that runs in browsers at near-native speed. It allows running code written in languages like C, C++, and Rust on the web alongside JavaScript.
Think of it as a high-performance engine for computationally intensive tasks in the browser.
## Why WebAssembly Exists
JavaScript is fast enough for most web tasks but struggles with heavy computation - video editing, 3D graphics, games, scientific simulations.
WebAssembly runs 10-100x faster than JavaScript for these tasks, enabling desktop-quality applications in the browser.
## How It Works
1. Write code in C++, Rust, or similar language
2. Compile to WebAssembly binary format
3. Load in browser alongside JavaScript
4. JavaScript calls WebAssembly functions for heavy tasks
JavaScript handles UI and DOM. WebAssembly handles computation.
## Real-World Usage
**Figma**: Design tool uses WASM for rendering. Feels as fast as native desktop apps.
**Google Earth**: Ported to web using WebAssembly. Full 3D globe in your browser.
**AutoCAD**: Engineering software running in browsers through WASM.
**Games**: Unity and Unreal Engine games compile to WASM for web deployment.
## When to Use WASM
**Use for**: Video/image processing, games, 3D rendering, scientific computing, porting existing C/C++ applications.
**Stick with JavaScript for**: Standard web development, UI logic, DOM manipulation, most business applications.
## Benefits
**Performance**: Near-native speed for computational tasks.
**Language Choice**: Use C++, Rust, or other languages beyond JavaScript.
**Portability**: Same binary runs everywhere - browsers, servers, edge computing.
## Limitations
**Not a JavaScript Replacement**: WASM complements JavaScript, does not replace it. Most web development stays in JavaScript.
**DOM Access**: Cannot directly manipulate the DOM. Must go through JavaScript.
**Debugging**: Harder to debug than JavaScript. Tooling is improving but not as mature.
## The Future
WebAssembly is growing but still niche. Most developers will never write WASM directly. But understanding it helps when performance becomes critical or when using tools built with WASM (like Figma).
For 95% of web development, JavaScript is sufficient. WebAssembly handles the remaining 5% where performance is critical.
