SvelteKit

Meta-Frameworks

The fastest way to build Svelte apps

weekly downloads958K

versionv2.52.2

licenseMIT

File-based routingAdapter systemEdge-ready

Overview

@sveltejs/kit is the official application framework for Svelte, providing a complete solution for building modern web applications. It combines frontend component rendering with backend capabilities like API routes and server-side rendering in a single cohesive package. The framework uses Vite for lightning-fast development with hot module replacement and implements automatic file-based routing where your project structure directly maps to URL routes.

The package emerged as the successor to Sapper, addressing lessons learned from earlier Svelte application development. It solves the problem of piecing together routing, data loading, server-side rendering, and deployment configurations by providing an integrated, opinionated solution. With over 950,000 weekly downloads, it has become the standard way to build production Svelte applications since reaching 1.0 stability.

SvelteKit targets developers building full-stack JavaScript applications who want the performance benefits of Svelte with minimal configuration overhead. The framework handles both static site generation and dynamic server rendering, making it suitable for everything from marketing sites to complex web applications. Its adapter system allows deployment to various platforms including Node.js servers, Vercel, Netlify, and Cloudflare Workers without changing your application code.

Quick Start

typescript

// src/routes/+page.server.ts
export async function load({ fetch }) {
  const response = await fetch('https://api.github.com/repos/sveltejs/kit');
  const repo = await response.json();
  return {
    stars: repo.stargazers_count,
    name: repo.name
  };
}

// src/routes/+page.svelte
<script lang="ts">
  export let data;
</script>

<h1>{data.name}</h1>
<p>Stars: {data.stars.toLocaleString()}</p>

// src/routes/api/hello/+server.ts
import { json } from '@sveltejs/kit';
import type { RequestHandler } from './$types';

export const GET: RequestHandler = async ({ url }) => {
  const name = url.searchParams.get('name') || 'World';
  return json({ 
    message: `Hello, ${name}!`,
    timestamp: new Date().toISOString()
  });
};

// svelte.config.js
import adapter from '@sveltejs/adapter-auto';

export default {
  kit: {
    adapter: adapter()
  }
};

Use Cases

Full-stack web applications: Build complete apps with frontend components, API endpoints, and database integration in one codebase. The load functions fetch data server-side before rendering, eliminating waterfall requests and improving perceived performance.

Static marketing sites with dynamic sections: Generate static HTML at build time for fast page loads while keeping certain routes server-rendered for personalized content or real-time data. The prerendering system handles this automatically based on your configuration.

Progressive web applications: Leverage built-in service worker support and automatic code-splitting to create fast, offline-capable apps. SvelteKit generates optimized bundles with only the JavaScript needed for each route.

Multi-platform deployment: Write your application once and deploy to different environments using adapters. Switch from a traditional Node.js server to serverless functions by changing one line in your config file.

Component libraries: Use SvelteKit's package mode to develop, test, and publish reusable Svelte component libraries to npm with proper TypeScript definitions and documentation.

Pros & Cons

Pros

+Exceptional developer experience with instant HMR updates via Vite and minimal boilerplate configuration
+File-based routing eliminates manual route setup and makes application structure immediately understandable
+Built-in SSR and data loading patterns solve common performance problems without third-party libraries
+Adapter system provides genuine deployment flexibility across platforms without code changes
+Strong TypeScript support with automatic type inference for routes and load functions

Cons

−Ecosystem smaller than React-based frameworks, with fewer third-party integrations and tutorials available
−Breaking changes between major versions have historically required significant migration effort
−Documentation for advanced server customization and edge cases can be sparse compared to mature frameworks
−Some deployment adapters have limitations or quirks specific to their hosting platform
−Learning curve for developers unfamiliar with Svelte's reactive paradigm and SvelteKit's conventions

Comparisons

astro vs @sveltejs/kitmeta-framework →nuxt vs @sveltejs/kitmeta-framework →

Install

bash

npm install @sveltejs/kit

bash

pnpm add @sveltejs/kit

bash

bun add @sveltejs/kit

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