Svelte Frontend Website Development
Svelte is a compiler, not a runtime framework. Svelte component code compiles to vanilla JavaScript without Virtual DOM. Result: smaller bundle, better performance, simpler code. Svelte 5 introduces Runes — new reactivity system.
Why Svelte is faster
React and Vue work through Virtual DOM — create virtual tree and diff with real. Svelte at compile time determines which DOM parts will change on state change and generates precise DOM updates:
<!-- Svelte compiles this into -->
<script>
let count = 0;
</script>
<button on:click={() => count++}>
Clicked {count} times
</button>
<!-- ...roughly like this JS: -->
// element.textContent = `Clicked ${count} times`;
// (direct update without diffing)
Svelte 5 Runes
Svelte 5 replaces implicit reactivity with explicit runes:
<script>
let count = $state(0); // reactive state
let doubled = $derived(count * 2); // computed
$effect(() => {
console.log('count changed:', count);
});
</script>
<button onclick={() => count++}>{count} × 2 = {doubled}</button>
Components and props
<!-- UserCard.svelte -->
<script>
let { name, age, onSelect } = $props();
</script>
<div class="card" role="button" onclick={onSelect}>
<strong>{name}</strong>
<span>{age} years</span>
</div>
<style>
/* Styles automatically scoped to component */
.card { padding: 16px; border-radius: 8px; }
strong { color: #1a1a2e; }
</style>
Stores
Global state via Svelte stores:
// stores/user.ts
import { writable, derived } from 'svelte/store';
export const user = writable(null);
export const isLoggedIn = derived(user, $user => !!$user);
// In component
import { user, isLoggedIn } from '../stores/user';
$: console.log($user); // $ subscription to store
Animations and transitions
Built-in CSS animation support:
<script>
import { fade, fly, scale } from 'svelte/transition';
import { tweened } from 'svelte/motion';
let visible = true;
const progress = tweened(0, { duration: 400 });
</script>
{#if visible}
<div transition:fly={{ y: -20, duration: 300 }}>Appearing</div>
{/if}
<progress value={$progress} />
Ecosystem
- SvelteKit — meta-framework SSR/SSG (analog of Next.js)
- Svelte Material UI — Material Design components
- Shadcn-Svelte — port of Shadcn/ui for Svelte
When to choose Svelte
- Interactive widgets for embedding in non-SPA sites
- Projects with strict bundle size requirements (browser extensions, email widgets)
- Teams valuing code simplicity over ecosystem size
- Animated and highly interactive UI
Timeline
Frontend on Svelte for SPA/widget (5–10 screens): 1–2 weeks. Project with SSR via SvelteKit, authorization, API integration: 2–5 weeks.