Introduction to Svelte

By Archie To, 2025-04-28. Last updated 2025-06-03.

ARCsoft recently came across a project that uses Svelte. The framework is pretty neat and it comes with many unique features compared to other frontend technologies. Let’s discover those features together in this article.

Disclaimer: I’m fairly new to Svelte myself, so the things I write here are what I’ve learned so far. If you spot anything that can be improved or clarified, feel free to send me feedback. I’ll happily make updates accordingly.

What is Svelte?

Most frontend frameworks like React and Vue work by running a virtual DOM in the browser, constantly comparing changes and updating the real DOM accordingly. Svelte takes a different approach: instead of doing all the heavy lifting in the browser, Svelte compiles your code to efficient, vanilla JavaScript at build time.

This means that your app doesn’t need a framework running in the background when the user interacts with it—everything is turned into plain, fast JavaScript. As a result, Svelte apps are generally smaller, faster, and simpler than apps built with traditional frameworks.

Here’s a tiny Svelte example:

<script>
  let count = 0;
</script>

<button on:click={() => count++}>
  Clicked {count} {count === 1 ? 'time' : 'times'}
</button>

That’s it! No special state management hooks, no “useEffect” or “useState” calls. Just regular variables that magically update your UI.

Why Svelte Over Other Frontend Frameworks?

Every framework has its strengths and weaknesses, and Svelte is no different. Here are a few reasons why you might choose Svelte:

  • Less boilerplate: You don’t have to constantly think about useState, useEffect, refs, or dependency arrays. Your variables are reactive by default.
  • Fast performance: Since Svelte compiles your code to minimal JavaScript, there’s no virtual DOM overhead. Your app feels responsive right out of the box.
  • Smaller bundle size: Because you’re not shipping a framework to the browser, Svelte apps tend to be much smaller compared to React or Vue apps.
  • More intuitive syntax: If you know basic HTML, CSS, and JavaScript, you can pick up Svelte quickly. There’s less of a “framework-specific” way of thinking.
  • Built-in reactivity: You don’t need external libraries for basic reactivity. Variables just “react” when their values change natively.

To put it simply, Svelte removes a lot of mental overhead and lets you focus more on building your app, not wrestling with the framework.

Of course, Svelte might not be the best fit for every situation. It’s still maturing compared to giants like React, and the ecosystem is smaller. But if you value speed and simplicity, it’s absolutely worth a try.

Main Features of Svelte

Here are some of the most exciting features that make Svelte stand out:

1. Code compilation

Instead of tracking and applying updates in the browser, Svelte does it when you build your app. It turns your .svelte components into optimized JavaScript that updates the DOM directly. This results in faster load times and better performance.

2. Native Reactivity

Variables in Svelte are reactive by default. If you assign a new value to a variable, the UI updates automatically—no extra API needed.

<script>
  let name = "World";
</script>

<h1>Hello {name}!</h1>

<input bind:value={name}>

Here, typing into the input automatically updates the heading without needing any special code.

3. Built-In Animation and Transitions

Svelte has built-in, easy-to-use support for transitions and animations. You can add beautiful effects with just one line:

<div transition:fade>
  Hello World!
</div>

No need to pull in heavy libraries like Framer Motion unless you want something super fancy.

4. Stores for Global State

While simple components use reactive variables, Svelte also provides stores for global state management. And it’s just as lightweight:

import { writable } from 'svelte/store';

export const count = writable(0);

Then inside any component, you can subscribe to that store easily.

5. SvelteKit for Fullstack Development

If you love Next.js for React, you’ll be happy to know that SvelteKit is the equivalent for Svelte. It offers routing, server-side rendering, static site generation, and even API routes—all powered by Svelte.

It’s still evolving fast, but SvelteKit is making Svelte a serious choice for production-grade apps.

Svelte vs SolidJS

At one point, I was tasked with comparing Svelte and SolidJS and choosing the better one as our main frontend framework for future projects. As a React enthusiast, I selected SolidJS as I found its hooks and component structure were more intuitive than Svelte’s.

Now that I have some development experience with Svelte, I’m somewhat drawn to the simplicity and the excellent utilities that it provides. Plus, Svelte has a more mature ecosystem than SolidJS. If I were to choose again, I would go with Svelte.

Conclusion

Svelte might not be the most mainstream framework yet, but it offers a refreshing take on building web apps—fast, clean, and enjoyable. It’s especially perfect for developers who prefer minimal configuration and maximum efficiency.

I’ll be diving deeper into Svelte in future posts (maybe building a simple app just like we did with SolidJS). If you’re curious about Svelte, definitely give it a shot. You might fall in love with the simplicity.

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