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A Quick In-Depth Introduction To WebAssembly

You must have heard the term “WebAssembly” if you’re a tech-junkie. However, do you know for sure what it is? In case your answer is No, then you have landed upon the absolutely correct place or page.

In the upcoming future, WebAssembly is going to play a big role in the Information Technology (IT) industry. Consequently, every web development company will use it. So it is important to understand the concept thoroughly in order to perform better in the future. Now, let’s move ahead and learn about WebAssembly in-depth. 

Key Takeaways

  • Approximately, 40 programming languages can compile to WebAssembly, as a result, coders can work in their comfort zone, which means you can use the language in which you’re master. 
  • WebAssembly never replaces JavaScript. On the contrary, to load WebAssembly modules some JavaScript codes are often required. 
  • WebAssembly works on all the popular browsers, as well as platforms. In addition, support from the experts or community is always available for WebAssembly when JavaScript is associated.
  • WebAssembly works on all the servers smoothly.  

Basic Concepts

This is very important to fully understand how the browser uses WebAssembly, especially for a full stack developer, we need to familiarize ourselves with some basic concepts about this code format before diving into it.

A few basic skills are required prior to developing with WebAssembly. These skills include understanding JavaScript and being comfortable working with a command-line interface. Knowledge of C or C++ is also advantageous.


Modules in WebAssembly are compiled in binary by the browser. They can be seen in the same way as ECMAScript modules, where they contain functions that can import or export other modules.

Stack Machine

As a stack machine, WebAssembly manages loops, arithmetic calculations, and memory accesses via an ISA.

Now, if you’re planning to access top-notch services includingWebAssembly, you can choose either offshoring vs outsourcing.

Let’s get started with the hottest topic “WebAssembly “

What is WebAssembly?

In simple terms, human-readable languages are often called an assembly, as opposed to machine code, which is a bunch of numbers.

This is a low-level assembly language with a compact binary format and performs nearly as well as native code. Furthermore, because WebAssembly is a new type of code, it runs on all modern browsers. By providing compilation targets for languages such as C/C++ & Rust, these languages can run on the web. WebAssembly is designed to work alongside JavaScript so that both work together smoothly. You must hire JavaScript developers who are well-versed with WebAssembly.


WebAssembly (abbreviation Wasm) is a binary function format, especially for stack-based virtual machines. Using Wasm for client and server application deployment on the web, programmers can compile languages and deploy them on the web.

Language Support in WebAssembly

A WebAssembly language is not meant to be written directly. Rather, it’s meant to be consumed by machines, so it’s an assembly language more than a high-level programming language. The LLVM implementation of WebAssembly is similar to the intermediate representation (IR) produced by the compiler infrastructure, rather than C or Java. In the future when you plan to hire software developers, consider those who are skilled with WebAssembly also. 

The most common use of WebAssembly is to write high-level code, which is then converted into WebAssembly. There are 3 main ways to do this:

Direct Compilation

The source code is compiled natively using the language’s own compiler toolchain. WASM can be generated natively from compilers that support languages such as Rust, C/C++, Kotlin/Native, and D.

Third-party Tools

There is no native WASM support in the language, but it can be converted to WASM with a third-party utility. Other languages like Java, Lua, and the .Net family all support it like this.

WebAssembly-Based Interpreter

Instead of translating the language directly into WebAssembly, an interpreter for the language is written in WebAssembly that runs code. It’s the most cumbersome approach since the interpreter can take up many megabytes of code, but it allows existing code written in the targeted language to run all but unchanged. Both Python and Ruby have interpreters for WASM.

To write code for WebAssembly somehow, break the code into three levels such as:

  • Binary format,
  • Text format,
  • High-level programming languages.

Advantages of Using WebAssembly 

The primary language running in the virtual machine has been JavaScript for the longest time; it has worked quite well for this purpose. However, newer use-cases have highlighted one of the main problems of JavaScript – its performance.

JavaScript is not capable of delivering near-native performance when running resource-intensive apps, such as 3D games, VR and augmented reality, and video editing. This issue gets even more critical when factoring in the compute costs of downloading, parsing, and compiling larger JavaScript-based applications.

In every browser, the code is interpreted by a JavaScript engine. However, JavaScript is not perfect for performing all tasks we need, so WebAssembly is ideal. Therefore, all the browsers including Google, Microsoft, Mozilla, and others are planning to launch a new binary format for the web because it renders great benefits compared to JavaScript.

Despite the fact that WebAssembly is entirely different from JavaScript, it’s supposed to run alongside JavaScript rather than as its replacement. That way, developers can use the best of both in their applications. WebAssembly has a compact binary format unlike JavaScript and is built upon a low-level, assembly-like language.

Together, these features enable WebAssembly to perform like native JavaScript. Increasingly, consumers aim for cloud-native, mobile-first applications, so near-native performance has become crucial to the success of some of these applications. For example, if you wish for a mobile app development solution, then these features are very vital.

Top Pros of WebAssembly

  • Near-Native Performance.
  • Security.
  • Easy Debugging.
  • Open-Source.
  • Hardware, Language, & Platform-independent.
  • Lightweight.

How WebAssembly Works? 

In order to understand how WebAssembly works, you would first need to understand how the JS (JavaScript) engine works. So without further ado, let’s get started.

How does the JS Engine Works?

To compile JavaScript code, the engine must perform a few things such as: –

The Parser – The code must first be passed through a parser. The parser evaluates each line of code line by line, checking for syntax errors and identifying the code types. If all of these criteria are met, an Abstract Syntax Tree (AST) is created.

AST to Intermediate Representation (IR) – The engine interpreter then transforms the AST into Bytecode, an intermediate representation of the code (an IR is an abstraction of machine code). 

Compiling the IR to Machine Code – Once the engine compiler takes the Bytecode, it converts it into a machine-readable format so that it can run on a computer.

How WASM Works?

Since WASM code goes directly to the compiler, it skips both the first and second steps, resulting in faster execution times.

Are you now wondering why WebAssembly skips 1 and 2 steps and why JavaScript doesn’t work the same way? Let’s find out.

This is due to the fact that JS is a dynamically-typed language, which means that the Parser will check the types of variables at runtime.

Unlike statically-typed languages, which declare types in advance, statically-typed languages ensure that types are known and checked during compilation.

This is how WASM works: –

  • Code is usually written in a statically typed language.
  • The WASM module is then generated.
  • The engine compiler can then run the code directly, skipping the parsing and the transformation to Intermediate Representation.

Why Opt For WebAssembly?

WebAssembly has attracted tremendous interest since all major browsers officially support it. Despite such demonstrations being interactive, they do not convey immediate applications for WebAssembly in the majority of today’s web applications. There are a lot of reasons why WebAssembly is becoming more common under the hood for otherwise ordinary web applications. Nevertheless, WebAssembly is not a panacea.

Below, we will highlight the top use cases for WebAssembly.

Efficiency and Speed

It is possible to deploy high-speed math functions in WebAssembly, for instance, if you already have a C-based function written in the back-end. The less critical, user-facing parts of the application can remain in JavaScript.


The sandbox environment makes sure that our browser passwords are safe, so modules are executed in a secure environment. 


It is an open language, and you are welcome to contribute to it by writing converters to the WASM format for your favorite languages.

Already in Browsers

Modules will be available from npm that are ready to use in the near future, which means they will always work.

Examples of WebAssembly

WASM aimed not to optimize websites, but rather to enhance browser performance (and other server-side runtimes such as Node.js).

examples of webassembly

The most use cases of WebAssembly includes: –

  • Video Editing
  • Game Development
  • AR / VR Live Applications
  • Music Editing & Streaming
  • Platform Emulation
  • Encryption
  • VPN
  • Image Recognition
  • Recording And Encoding Audio
  • Encoding Video
  • Rendering 3D Objects In Real-time
  • Re-Encoding Images And AnnotatiOn The Fly
  • Editing ng PDFs
  • Creating A Fully-featured Text Editor
  • Visualizing Data In Real-time
  • Doing Real-time Physics Simulation

Running In The Browser

In order to run a Wasm module in the browser, you must load, instantiate, and invoke the .wasm file. You can choose from the multiple loading methods described in the JavaScript API.

webassembly running in the browser

Here’s an example script that loads answer.wasm in the browser and displays the output (the number “42”) in an alert box:

Running Outside The Browser

WebAssembly was designed primarily to provide developers with access to advanced applications. However, Wasm modules can be run on servers as well.

webassembly running outside the browser

For example, you can run answer.wasm using only a few lines of code in Node.JS:

Deployment of WebAssembly 

  • The barcode scanner implemented by eBay is universal.
  • With WebAssembly, Google Earth runs on all browsers.
  • WebAssembly can run both the Unity and Unreal engines. In fact, the Unreal Epic Zen Garden demo has even been ported.
  • The Doom 3 engine is now available in WebAssembly. A demo is available online.
  • The browser-based game-design tool Construct3 enables you to create custom games.

5 Must-Know Things About Web Assembly

Source code: It is what a developer writes to create a software solution.

Compiler: The process of converting source code into an assembly, bytecode, or machine code.

Assembly: Low-level source language designed for a particular machine or application.

Bytecode: Codes that can be run by other applications that are represented in binary form.

Machine code: A binary representation of a program that can run on hardware directly.

8 Objects – Key to WebAssembly

WebAssembly.Module – A precompiled stateless WebAssembly code is present in this object.

WebAssemly.Global – The object represents an instance of a global variable that can be accessed from both JavaScript and WebAssembly.Module, and that can be exported and imported.

WebAssembly.Instance – The object represents an executable, stateful instance of WebAssembly.Module.

WebAssembly.Memory – WebAssembly.Instance accesses raw bytes of memory with the help of the ArrayBuffer or SharedArrayBuffer object.

WebAssembly.Table – The object stores function references as a JavaScript wrapper.

WebAssembly.CompileError – During encoding or validation, there may have been an error.

WebAssembly.LinkError – In the module instantiation process, this object indicates an error.

WebAssembly.RuntimeError – WebAssembly throws this object when a trap is specified.

The Final Thought

Although WebAssembly has not flown high yet, it is definitely on the way. WebAssembly is slowly taking over cloud computing and could also invade the blockchain market soon. However, this will not have an equal impact because it is a low-level language designed for a compile target. Since JavaScript and WebAssembly integrate so smoothly, some web developers might not realize they are using WASM as well already.