How to Use WebAssembly to Boost Your Web App's Performance published 2/28/2023 | 7 min read

What is WebAssembly?

WebAssembly, or simply "Wasm" is a new type of code that can be used in web browsers (similar to JavaScript), designed to improve the performance of web applications. It was first announced by Mozilla in 2015, and since then has gained increasing popularity among web developers.

WebAssembly is a binary format, which means it is designed to be executed more quickly by computers than traditional text-based formats such as JavaScript. This makes it ideal for use in web applications that need to be responsive and fast.

Key strengths:

Key weaknesses:

Despite these challenges, WebAssembly is an exciting technology that has the potential to transform the way we build web applications. As more developers become familiar with it, and as tooling and support continue to improve, we can expect to see even more powerful and performant web applications built with WebAssembly.

Example use cases for WebAssembly in web apps:

These are just a few examples of how WebAssembly can be used in web apps. As the technology matures, we can expect to see even more innovative use cases emerge.

WebAssembly Hello world example in C lang:

This is a simple function written in C that calculates the sum of two numbers:

int add(int a, int b) {
  return a + b;

To compile this code into Wasm, you would use a tool such as Emscripten. Here's the command to compile the code:

emcc add.c -s WASM=1 -o add.wasm

This command generates the add.wasm file, which contains the compiled Wasm code.

To run this Wasm code in the browser, you can create a simple HTML file that loads the Wasm code using JavaScript. Here's an example HTML file:

<!DOCTYPE html>
    <meta charset="UTF-8">
    <title>WebAssembly Example</title>
        .then(response => response.arrayBuffer())
        .then(bytes => WebAssembly.instantiate(bytes))
        .then(results => {
          const add = results.instance.exports.add;
          console.log(add(2, 3)); // Output: 5

Tools and frameworks that support WebAssembly


In conclusion, WebAssembly is a powerful technology that has revolutionized the way we think about web application development. Its benefits include portability, a safe and sandboxed environment, interoperability with multiple programming languages, and small file size. However, it also has its drawbacks, including limited access to browser APIs, lack of garbage collection, a steep learning curve, and debugging challenges.

Despite these challenges, WebAssembly has the potential to greatly improve the performance and capabilities of web applications, making it a valuable addition to any web developer's toolkit. With support from major browsers and numerous tools and frameworks, it is easier than ever to start incorporating WebAssembly into your web applications. So, whether you're building a game, a media player, or a complex web app, consider exploring the possibilities of WebAssembly to take your web development to the next level.

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