The Rise of WebAssembly: How It's Changing Web Development

In this blog, we explore how WebAssembly, in tandem with the power of Rust programming, is transforming modern web development.

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The Rise of WebAssembly: How It's Changing Web Development


In web development, JavaScript has reigned as the real programming language for client-side scripting. While it’s unique versatile and capable, JavaScript wasn’t originally designed for tasks that required large amounts of computing power or performance. As modern web applications become more robust and interactive—think processing video in real-time, rendering 3D models, or creating scientific models—the limits of JavaScript performance have become apparent and expressed greatly

Limitations of JavaScript for High-Performance Tasks

  1. Single-Threaded Nature: JavaScript can only do one thing at a time, making it less efficient for heavy computational tasks, even with some workarounds like Web Workers.
  2. Garbage Collection: Automatic memory cleanup, or garbage collection, can cause random delays, which is a problem for real-time apps needing consistent speed.
  3. Runtime Interpretation:  JavaScript code runs on the fly rather than being pre-compiled, making it slower for tasks that need heavy calculations or data manipulation.
  4. Limited Access to Hardware Resources: For security, JavaScript can't fully utilize computer hardware, affecting performance in compute-heavy applications.

WebAssembly: A Fix for JavaScript's Limits

  1. Faster Performance: WebAssembly runs quickly, giving web apps almost native-level speed by using hardware more effectively.
  2. Low-Level Speed: Its low-level binary format allows for fast execution, ideal for things like 3D rendering and complex calculations.
  3. Language Options: You can write code in various languages like C, C++, and Rust, and still run it smoothly on the web.
  4. Secure: WebAssembly runs in a safe, sandboxed environment, making it secure for client-side execution.

WebAssembly bridges the gap between JavaScript's limitations and modern hardware, setting the stage for high-performance web apps.

Real-World Examples

Design Tools: Figma

  • Figma uses WebAssembly to run its design tool directly in the browser, achieving near-native performance and enabling seamless user experiences.

Gaming: Unity Engine

  • Unity leverages WebAssembly to bring complex, graphics-intensive games into the browser without requiring users to download or install software.

Real-time Communication: Zoom

  • Zoom's WebAssembly implementation allows for high-quality, real-time video conferencing directly in the browser, eliminating the need for external software.

Getting Started


In this article, we'll delve into the intriguing world of WebAssembly through the lens of Rust programming.
is a high-performance systems programming language renowned for its focus on safety, concurrency, and speed. It offers the advantages of memory safety without compromising on computational efficiency.
, commonly referred to as Wasm, is a cutting-edge binary instruction set tailored for stack-based virtual machines. Created to be a universal compilation target for languages like Rust, WebAssembly opens the door for high-level, web-optimized client and server applications.
Together, Rust and WebAssembly provide an exciting landscape for modern web development, combining the best of both worlds—robust, safe code and high-speed execution. Stay tuned as we unpack how these two technologies intersect to redefine the boundaries of web programming.


1. Install Rust and Cargo: Installation Guide
2. Install wasm-pack: Run cargo install wasm-pack

Create a ToDo app in WebAssembly with Rust

1. Create a new Rust library project:

cargo new --lib wasm_todo
cd wasm_todo

2. Open the directory in your favorite IDE and update `Cargo.toml`:

wasm-bindgen = "0.2"

crate-type = ["cdylib"]

3. Implement the ToDo logic in `src/`:

extern crate wasm_bindgen;
use wasm_bindgen::prelude::*;
use std::collections::HashMap;

pub struct TodoApp {
    items: HashMap<String, bool>,

impl TodoApp {
    pub fn new() -> TodoApp {
        TodoApp {
            items: HashMap::new(),

    pub fn add_item(&mut self, item: String) {
        self.items.insert(item, false);

    pub fn remove_item(&mut self, item: String) {

    pub fn toggle_status(&mut self, item: String) {
        if let Some(status) = self.items.get_mut(&item) {
            *status = !*status;

    pub fn list_items(&self) -> String {
        self.items.iter().map(|(k, v)| format!("{}: {}", k, 

4. Build WebAssembly package:

wasm-pack build

After running this command, you should see a `pkg` folder generated inside your project. This folder contains the compiled WebAssembly file and the JavaScript glue code.

5. HTML and JavaScript

Create a file named `index.html` in your project folder and add this HTML:

<!DOCTYPE html>
    <title>Todo App</title>
    <h1>Todo App</h1>
    <input id="newItem" type="text" placeholder="New todo item">
    <button onclick="addItem()">Add Item</button>
    <button onclick="removeItem()">Remove Item</button>
    <button onclick="toggleStatus()">Toggle Status</button>
    <ul id="todoList">
    <script type="module">
        import init, { TodoApp } from './pkg/wasm_todo.js';
        let todoApp;

        async function run() {
            await init();
            todoApp = new TodoApp();

        window.addItem = function() {
            const newItem = document.getElementById("newItem").value;
        window.removeItem = function() {
            const newItem = document.getElementById("newItem").value;

        window.toggleStatus = function() {
            const newItem = document.getElementById("newItem").value;

        function renderList() {
            const listItems = todoApp.list_items();
            const listArray = listItems.split("\n").filter(Boolean);
            const ulElement = document.getElementById("todoList");
            ulElement.innerHTML = '';
            for (const item of listArray) {
                const liElement = document.createElement("li");
                liElement.textContent = item;


6. Run the App

To run the app without npm, you can use Python's SimpleHTTPServer or any other simple HTTP server.
Run this command to start a server with Python 3.x:
python3 -m http.server
Then navigate to http://localhost:8000 in your web browser. You should see your to-do app. You can add tasks using the input field and button.
This is a very basic example, but hopefully, it gives you a good starting point for building more complex applications using Rust and WebAssembly.


  • Learning Curve: While Rust offers many advantages, it has a steeper learning curve, especially for those new to systems programming.
  • Interoperability: Interacting between JavaScript and Rust-compiled WebAssembly might require some boilerplate. Tools like `wasm-bindgen` help, but understanding the nuances is essential.
  • Debugging: Debugging WebAssembly code isn't as straightforward as traditional JavaScript. However, browser devtools are rapidly improving in this area.
  • Package Size: WebAssembly packages can sometimes be large, especially if they include parts of the Rust standard library. Techniques like tree shaking and using `wasm-opt` can help reduce the size.
  • Performance Expectations: While WebAssembly can be faster than JavaScript for many tasks, it's essential to understand that not all computations will see performance gains. Some tasks might even be slower in WebAssembly.


Future Outlook

WebAssembly is still a relatively new technology, but it's evolving quickly. As it gains more traction, we can expect its ecosystem to mature, resulting in increasingly powerful and efficient web applications. Major browser vendors are continually updating their WebAssembly engines, which means we can anticipate better performance and additional features in the near future.
Several upcoming advancements could revolutionize the way we use WebAssembly:

  1. Thread Support: WebAssembly is working towards full multithreading support, which will allow developers to take full advantage of modern multi-core processors.   
  2. Garbage Collection: Future implementations may include garbage collection, making it easier to port languages like Java and C# to the web, thereby expanding its utility and versatility.
  3. Streaming Compilation: This will enable WebAssembly modules to be compiled while being downloaded, resulting in faster load times for web applications.    
  4. Integration with Web APIs: Future versions could allow direct manipulation of the DOM and other Web APIs, reducing the current reliance on JavaScript for these tasks.


WebAssembly is changing the landscape of web development in a monumental way. Gone are the days when JavaScript had a monopoly on client-side web development. With the advent of WebAssembly, developers can now leverage languages like C, C++, and Rust to write high-performance applications that run smoothly in the browser.
The technology is still in its infancy but has shown great promise in fields like gaming, video and image editing, real-time communication, and even server-side applications. As WebAssembly continues to mature, it will no doubt play an increasingly integral role in shaping the future of both web and possibly server-side development.
In a nutshell, WebAssembly isn't just an alternative to JavaScript; it's a powerful supplement that allows developers to optimize performance and offer users a richer, smoother experience. It is an exciting time to be a web developer as we stand on the brink of what could very well be a new era in web development, driven by the limitless possibilities that WebAssembly brings.
By keeping an eye on this rapidly evolving technology, web developers can position themselves at the forefront of a game-changing revolution in web application design and functionality.

Hello, I'm Rekib Ahmed. I am passionate about all things tech, with an interest in cooking, reading, and the always-changing world of innovation.

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