My First Web Assembly Program

Udit NimbalkarUdit Nimbalkar
4 min read

Let’s Start Decoding….

As someone who loves to tinker with C++, I always thought of it as a language confined to desktop builds and backend power. But Web Assembly (Wasm) changed the rules of the game—and I recently took my first dive into compiling and running C++ code inside a browser. The experience? Magic.

🧠 What is Web Assembly, anyway?

Web Assembly is a binary instruction format that allows code written in languages like C, C++, and Rust to run on the web at near-native speed. It opens doors for building web apps that are fast, efficient, and not limited to JavaScript alone.

In essence, it gives traditional systems programmers a passport into the world of frontend development—with performance that can keep up with native applications.

🔧 Before Frontend, Backend, or DevOps — We Are Engineers

In the world of software, titles come and go. Today you might be a frontend wizard, tomorrow a backend architect, and next week knee-deep in CI/CD pipelines. But underneath all that, we're engineers first. That means we solve problems, optimize systems, and build things that matter—regardless of where that code runs. Learning something like Web Assembly isn't just about switching stacks; it’s about sharpening our mindset as creative problem-solvers in an ever-evolving digital landscape.

💻 Should Frontend Developers Learn Web Assembly?

Short answer: Yes—at least a little.

While Web Assembly doesn’t replace JavaScript or TypeScript, it complements them. If you're a frontend developer working with graphically intensive apps, data visualization, video editing, gaming, or even AI inferencing in the browser, WASM can offer massive performance gains. Plus, understanding how Web Assembly integrates with the DOM and JS makes you a more well-rounded developer.

Even knowing when not to use it is a skill in itself.

🎯 How It Sets You Apart as a Frontend Developer

Most Frontend developers are comfortable with HTML, CSS, and JavaScript—but very few venture into low-level performance tuning. By adopting Web Assembly, you place yourself in a unique niche:

  • You’re not just styling pixels—you’re optimizing pipelines.

  • You can bridge native logic into the browser without rewriting legacy code.

  • You're equipped for hybrid roles at the intersection of frontend, systems, and performance-critical development.

WebAssembly makes you stand out not just in what you build—but in how deeply you understand what powers modern web platforms.

🛠️ Setting Up the Stage: Installing Emscripten

To compile C++ to WASM, I used the Emscripten SDK (emsdk). Here’s the basic setup:

git clone https://github.com/emscripten-core/emsdk.git
cd emsdk
emsdk install latest
emsdk activate latest
./emsdk_env.sh   # Use emsdk_env.bat on Windows

Once that’s done, you’ll have access to emcc, the Emscripten compiler.

👨‍💻 Writing My First Program

Let’s go with the classic:

#include <iostream>
int main() {
  std::cout << "Hello, WebAssembly!" << std::endl;
  return 0;
}

To compile this into Web Assembly:

emcc hello.cpp -o hello.html

This creates:

  • hello.wasm — your compiled Web Assembly binary

  • hello.js — JavaScript glue code for loading the .wasm module

  • hello.html — a basic HTML page to tie it all together

🌐 Serving the Web Assembly Page with an HTTP Server

You can’t open hello.html by double-clicking it—browsers will block .wasm file access via file://. You need a proper local HTTP server.

Here are 3 easy options:

✅ Option 1: Python (if installed)

python -m http.server 8080

Then visit http://localhost:8080/hello.html

✅ Option 2: Node.js with http-server

npm install -g http-server
http-server .

This serves your current directory on http://localhost:8080

✅ Option 3: Live Server in VS Code

If you use Visual Studio Code:

  1. Install the Live Server extension.

  2. Right-click hello.htmlOpen with Live Server

Super convenient—and it auto-reloads changes while you develop.

🌍 Real-World Examples of Web Assembly in Action

Web Assembly is already used in production by global companies:

  • 🕹️ Unity: Runs full 3D games in the browser via Web Assembly export.

  • ✏️ Figma: Uses Wasm for real-time collaborative design performance.

  • 📐 AutoCAD Web: Autodesk brought its powerful CAD tools to the web using Web Assembly.

  • 🔐 1Password: Uses Wasm for secure client-side encryption in-browser.

  • 🧠 TensorFlow.js: Leverages Web Assembly for blazing-fast ML model inference.

  • 🧬 Bam.bio: In-browser genomics analysis using native tools compiled to Wasm.

💡 Why This Matters

Web Assembly opens doors to:

  • ⚡ High-performance computing in the browser

  • 🔁 Code reuse from native platforms to web

  • 📉 Smaller JavaScript bundles through smart module offloading

  • 🌍 Cross-platform, install-free apps with native-like speed

If you’re building games, simulations, editors, or processing-heavy web apps—Web Assembly is your secret weapon.

🧭 What’s Next?

Now that I’ve dipped my toes in Web Assembly, I’m dreaming big—maybe building a graphical demo, interactive game, or even bringing my old C++ logic to the web with a sleek frontend UI.

I used to think C++ had no business in the browser. Turns out, it just needed a passport—and Web Assembly stamped it in.


Thanks for reading!

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Udit Nimbalkar
Udit Nimbalkar