{"id":22813160,"date":"2026-01-20T09:00:19","date_gmt":"2026-01-20T17:00:19","guid":{"rendered":"https:\/\/thenewstack.io\/?p=22813160"},"modified":"2026-01-20T07:27:09","modified_gmt":"2026-01-20T15:27:09","slug":"webassembly-vs-javascript-testing-side-by-side-performance","status":"publish","type":"post","link":"https:\/\/thenewstack.io\/webassembly-vs-javascript-testing-side-by-side-performance\/","title":{"rendered":"WebAssembly vs. JavaScript: Testing Side-by-Side Performance"},"content":{"rendered":"

When we talk about WebAssembly<\/a> (Wasm), we often describe it as “near-native speed” and “faster than JavaScript.” But what does that actually look like in practice?<\/p>\n

Before we get into where Wasm excels, let’s level-set: JavaScript is still a developer’s best friend when it comes to UI. It was built to manipulate the DOM (the web’s Document Object Model) and handle CSS updates, and it does that job successfully. But we’re watching the demands of the browser change in real time. JavaScript was created in 1995 to add simple interactivity to text pages. Today, we’re asking browsers to process 4K video and run complex math that Brendan Eich (JavaScript’s creator<\/a>) never envisioned.<\/p>\n

I’ve already written a basic tutorial on how Wasm can boost your JavaScript app’s performance<\/a>. Following on from that, now I will do some speed comparisons between Wasm and JavaScript.<\/p>\n

Introduction to the Wasm vs. JS Tutorial<\/h2>\n

When you move past UI logic and into heavy data processing, JavaScript needs a partner. That’s where WebAssembly comes in. But how much faster is Wasm than JavaScript in a real-world scenario? Let’s find out.<\/p>\n

For this project, we’re building a browser-based image processor designed to handle two distinct types of operations:<\/p>\n