Your First WebAssembly Program and Web App (Written, Tested, and Deployed Entirely in the Web Browser)

WebAssembly (WASM) allows compiled languages like C, C++, and Rust to run at near-native speeds directly inside a web browser, turning it into a computational platform. This technology enables developers to reuse high-performance code for simulations, data analysis, and scientific computing, distributing complex applications as simple webpages. This tutorial provides a hands-on guide to compiling a C program into WASM using Emscripten. The entire process is conducted online within GitHub Codespaces, requiring only a web browser and a GitHub account to write, test, and deploy a web app.