SvelteKit Explained — Full-Stack Svelte Framework

In this tutorial, you will learn about SvelteKit Explained. We cover key concepts, practical examples, and best practices to help you master this topic.

SvelteKit is the official Svelte framework for building web applications with SSR, SSG, SPA modes, API routes, form actions, and optimized production builds.

What You'll Learn

• SvelteKit project structure
• +page, +layout, +server files
• SSR, SSG, and SPA modes
• Server endpoints (GET, POST)
• Form actions
• Deployment adapters

Why It Matters

SvelteKit extends Svelte with routing, server-side rendering, and API capabilities. It is the recommended way to build production Svelte applications with SEO and performance optimization.

<!-- src/routes/+page.svelte -->
<script>
  export let data;
</script>

<h1>Welcome to SvelteKit</h1>
<p>Server-rendered at: {data.serverTime}</p>

// src/routes/+page.server.js
export function load() {
  return {
    serverTime: new Date().toISOString(),
    posts: await fetch("https://api.example.com/posts").then(r => r.json()),
  };
}

// src/routes/api/posts/+server.js
import { json } from "@sveltejs/kit";

export async function GET() {
  const posts = await db.getPosts();
  return json(posts);
}

export async function POST({ request }) {
  const body = await request.json();
  const post = await db.createPost(body);
  return json(post, { status: 201 });
}

Expected output: A SvelteKit app with SSR-rendered pages, server data loading, and REST API endpoints.