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App.svelte
 
compile
App.js
 
No Runtime · compile-time transform
Svelte

Svelte FrontendWrite less code. No virtual DOM. Truly reactive.

Svelte is a compiler, not a framework — it transforms your components into tight, efficient vanilla JavaScript at build time. No runtime overhead, no virtual DOM, just the smallest possible output that does exactly what you wrote.

Svelte takes a radically different approach to building UIs — it's a compiler that transforms your declarative components into highly efficient, imperative vanilla JavaScript at build time. There's no virtual DOM diffing at runtime, no framework overhead shipped to the browser. The result is tiny bundles and blazing-fast updates. Svelte 5 introduces runes, a signals-based reactivity system that's both more explicit and more powerful than Svelte 4's implicit reactivity. With SvelteKit for full-stack apps, Svelte is a compelling choice for teams that prioritize performance and developer experience.

Quick start

bash
npx sv create my-app
cd my-app
npm install
npm run dev

Read the full documentation at svelte.dev/docs

Compile-time reactivity

Svelte shifts reactivity to the compiler — no virtual DOM diffing, just surgical DOM updates at build time.

Minimal bundle size

No runtime framework shipped to the browser — your bundle contains only the code your components actually use.

Built-in transitions & animations

First-class transition directives for enter/exit animations, crossfades, and spring physics without extra libraries.

Svelte 5 runes

$state, $derived, and $effect runes give you explicit, fine-grained reactivity with clear data flow.

Scoped styles by default

CSS written in a Svelte component is automatically scoped — no class name collisions, no CSS-in-JS overhead.

Framework-agnostic use

Compile Svelte components as custom elements and use them in React, Vue, or vanilla HTML projects.

Why it's hard

Smaller ecosystem than React/Vue

While growing rapidly, Svelte has fewer third-party component libraries, form solutions, and enterprise tooling compared to React. You'll build more from scratch or adapt generic JS libraries.

Svelte 4 to Svelte 5 migration

Svelte 5's runes ($state, $derived, $effect) replace the implicit reactivity model. Migrating existing codebases requires rethinking reactive declarations and stores.

Limited TypeScript template checking

Svelte's template language has improving but still imperfect TypeScript support — complex generics and event typing can be frustrating compared to TSX.

SSR edge cases in SvelteKit

Browser-only APIs, third-party script loading, and adapter differences between Vercel/Cloudflare/Node can create subtle SSR issues that are hard to debug.

Best practices

Adopt Svelte 5 runes for new projects

$state, $derived, and $effect give you explicit, fine-grained reactivity that's easier to reason about and debug than Svelte 4's implicit model.

Use SvelteKit for anything beyond a widget

SvelteKit provides routing, SSR, code splitting, and deployment adapters. There's no reason to wire these up manually for a Svelte project.

Keep components small and composable

Svelte's scoped styles and low overhead make small components practically free. Prefer many small components over fewer large ones.

Leverage server-only load functions

SvelteKit's +page.server.ts keeps secrets, database calls, and heavy logic off the client — use it by default and move to universal load only when needed.

Frequently asked questions




Want to build with Svelte?

Talk to our engineering team about your Svelte architecture. We'll respond within 24 hours.

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