# Svelte/SvelteKit Full-Stack Developer

Build full-stack web apps with Svelte and SvelteKit. Minimal runtime overhead, reactive components, and server-side rendering. The most admired frontend framework of 2025.

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## Metadata

**Title:** Svelte/SvelteKit Full-Stack Developer
**Category:** skills
**Author:** JSONbored
**Added:** October 2025
**Tags:** svelte, sveltekit, frontend, full-stack, reactive
**URL:** https://claudepro.directory/skills/svelte-sveltekit-fullstack

## Overview

Build full-stack web apps with Svelte and SvelteKit. Minimal runtime overhead, reactive components, and server-side rendering. The most admired frontend framework of 2025.

## Content

SVELTE/SVELTEKIT FULL-STACK DEVELOPER SKILL
WHAT THIS SKILL ENABLES
Claude can build reactive web applications using Svelte's compile-time approach and SvelteKit's full-stack framework. Svelte compiles components to vanilla JavaScript at build time, resulting in minimal runtime overhead and exceptional performance. SvelteKit adds file-based routing, server-side rendering, API routes, and adapters for any platform. From simple components to production apps with authentication and databases, Claude handles the Svelte ecosystem end-to-end.
PREREQUISITES
Required:
• Claude Pro subscription or Claude Code CLI
• Node.js 18+ (20+ recommended)
• npm or pnpm package manager
• Basic JavaScript knowledge
What Claude handles automatically:
• Creating reactive Svelte components with stores
• Building SvelteKit routes with +page.svelte files
• Implementing server-side logic in +page.server.ts
• Setting up form actions with progressive enhancement
• Adding authentication with hooks and load functions
• Configuring database connections and ORMs
• Implementing real-time features with Svelte stores
• Deploying to Vercel, Netlify, or Node servers
HOW TO USE THIS SKILL
Reactive Component Development
Prompt: "Create Svelte component for user profile with: editable bio, avatar upload with preview, reactive form validation, and optimistic UI updates. Use Svelte stores for state."
Claude will:
1) Create component with $: reactive statements
2) Set up writable stores for form state
3) Add two-way binding with bind:value
4) Implement file upload with FileReader
5) Add reactive validation with $:
6) Show optimistic updates
7) Handle submission with fetch
SvelteKit Full-Stack App
Prompt: "Build SvelteKit blog with: file-based routing, Markdown posts with frontmatter, server-side API routes for CRUD, authentication with JWT, and SQLite database with Prisma."
Claude will:
1) Set up SvelteKit project structure
2) Create +page.svelte routes
3) Add +page.server.ts load functions
4) Implement API routes in +server.ts
5) Configure Prisma with SQLite
6) Add authentication hooks
7) Parse Markdown with gray-matter
Form Handling with Actions
Prompt: "Create SvelteKit form for product creation with: server-side validation, progressive enhancement (works without JS), file uploads, and optimistic UI. Show errors next to fields."
Claude will:
1) Create form in +page.svelte
2) Add form action in +page.server.ts
3) Implement server-side validation
4) Use enhance for progressive enhancement
5) Add file upload handling
6) Display field-specific errors
7) Show success messages
Real-Time Dashboard
Prompt: "Build real-time analytics dashboard with Svelte: WebSocket connection, reactive charts with Chart.js, derived stores for calculated metrics, and auto-refreshing data every 30s."
Claude will:
1) Set up WebSocket in SvelteKit
2) Create writable stores for data
3) Add derived stores for calculations
4) Integrate Chart.js reactively
5) Implement auto-refresh with setInterval
6) Add connection status indicator
7) Handle reconnection logic
TIPS FOR BEST RESULTS
1) Use Reactive Statements: The $: syntax automatically re-runs when dependencies change. Use for derived values, side effects, and reactive logic.
2) Embrace Two-Way Binding: bind:value, bind:checked, bind:group simplify form handling. No need for onChange handlers.
3) Stores for Global State: Use writable, readable, or derived stores instead of React Context. Access with $ prefix in components.
4) Server Load Functions: Fetch data in +page.server.ts load functions for SSR. Access with data prop in components.
5) Form Actions Over APIs: SvelteKit form actions provide progressive enhancement. No JavaScript required for basic functionality.
6) Compile-Time Optimization: Svelte compiles to optimal JavaScript. Avoid runtime overhead of virtual DOM. Components are just functions.
COMMON WORKFLOWS
E-Commerce Store

 "Build SvelteKit e-commerce with:
 1. Product catalog: +page.svelte with load function, search/filter
 2. Product detail: dynamic [slug]/+page.svelte route
 3. Cart: writable store with localStorage persistence
 4. Checkout: form actions with Stripe integration
 5. Auth: hooks for JWT validation, protected routes
 6. Admin: +layout.server.ts for role-based access
 7. Database: Prisma with PostgreSQL
 8. Images: static adapter with CDN"

SaaS Dashboard

 "Create multi-tenant SvelteKit SaaS:
 1. Auth: +hooks.server.ts for session management
 2. Multi-tenant: load function filters by tenant ID
 3. Dashboard: reactive charts with derived stores
 4. Settings: form actions for account updates
 5. API: +server.ts routes for external integrations
 6. Billing: Stripe webhooks in API routes
 7. Real-time: Server-Sent Events for notifications
 8. Deploy: Node adapter with PM2"

Static Site Generator

 "Build Svelte static site generator:
 1. Content: Markdown files with frontmatter
 2. Processing: +page.server.ts loads and parses MD
 3. Templates: layout components for post types
 4. Navigation: derived store from post metadata
 5. Search: client-side with Fuse.js
 6. RSS: +server.ts generates feed.xml
 7. Sitemap: prerender all routes
 8. Deploy: Static adapter to Netlify"

Real-Time Collaboration

 "Build collaborative doc editor with Svelte:
 1. Editor: rich text with ProseMirror
 2. Sync: WebSocket for real-time updates
 3. Presence: writable store showing active users
 4. Conflict resolution: operational transforms
 5. Persistence: auto-save to database
 6. Auth: session-based with refresh tokens
 7. Rooms: dynamic [roomId] routes
 8. Cursor positions: reactive SVG overlays"

TROUBLESHOOTING
Issue: "Reactive statements not updating when I expect"
Solution: Ensure reactive statement depends on reactive value ($: result = calculate(value), not const). Use = for assignment in reactive block. Check that dependencies are in scope. Array/object mutations need reassignment: items = [...items, newItem].
Issue: "Load function data not available in component"
Solution: Export data prop in +page.svelte: export let data;. Check +page.server.ts returns object from load(). Verify route has +page.server.ts file. Use $page.data for nested layouts.
Issue: "Form action not being called"
Solution: Add name to form action: ``. Export actions in +page.server.ts. Use enhance from $app/forms for progressive enhancement. Check method is POST.
Issue: "Stores not persisting across page navigation"
Solution: Use writable store in separate .ts file, not component. Import same store instance everywhere. For persistence, sync to localStorage with custom store. Check SvelteKit isn't destroying store on navigation.
Issue: "Deployment build failing with adapter errors"
Solution: Install correct adapter (@sveltejs/adapter-node, -vercel, -static). Check svelte.config.js has adapter configured. Verify build command in package.json. For static, ensure all routes are prerenderable.
LEARN MORE
• Svelte Official Tutorial (https://svelte.dev/tutorial)
• SvelteKit Documentation (https://kit.svelte.dev/docs)
• Svelte GitHub Repository (https://github.com/sveltejs/svelte)
• SvelteKit Examples (https://github.com/sveltejs/kit/tree/master/examples)
• Svelte Society Recipes (https://sveltesociety.dev/recipes)
• Svelte REPL (https://svelte.dev/repl)
KEY FEATURES
? Compile-time optimization with zero runtime overhead
? Reactive programming with $: syntax for auto-updates
? SvelteKit file-based routing with SSR and SSG
? Form actions with progressive enhancement
REQUIREMENTS
? Node.js 18+
? @sveltejs/kit ^
? svelte ^
? vite ^
INSTALLATION
CLAUDE DESKTOP:
1) Create SvelteKit project: npm create my-app
2) Choose TypeScript, ESLint, Prettier in prompts
3) Ask Claude: 'Create Svelte component for [your feature]'
4) Run dev server: npm run dev
CLAUDE CODE:
1) npm create my-app
2) cd my-app && npm install
3) npm install -D @sveltejs/adapter-node prisma
4) npx prisma init (if using database)
USE CASES
? Building reactive dashboards with minimal JavaScript
? Full-stack apps with authentication and databases
? Static sites with Markdown content processing
TROUBLESHOOTING
1) Reactive statements not updating
 Solution: Ensure reactive statement uses $: syntax and depends on reactive value. Array/object mutations need reassignment: items = [...items, newItem]. Check dependencies are in component scope.
2) Load function data not available
 Solution: Export data prop in +page.svelte: export let data;. Verify +page.server.ts returns object from load(). Check route has server file. Use $page.data for nested layouts.
3) Form action not being called
 Solution: Add action name to form: . Export actions in +page.server.ts. Use enhance from $app/forms. Verify method is POST.
USAGE EXAMPLES
1) Reactive Counter Component
 Language: javascript
 Code:

 let count = 0;

 // Reactive statement - automatically re-runs when count changes
 $: doubled = count * 2;
 $: console.log(`Count is now ${count}`);

 function increment() {
 count += 1;
 }
 Count: {count}
 Doubled: {doubled}
 div {
 padding: 1rem;
 }
 button {
 background: #ff3e00;
 color: white;
 border: none;
 padding: 0.5rem 1rem;
 cursor: pointer;
 }

2) SvelteKit Page with Server Load
 Language: typescript
 Code:

 // src/routes/posts/+page.server.ts
 import type { PageServerLoad } from './$types';
 import { prisma } from '$lib/server/database';
 export const load: PageServerLoad = async () => {
 const posts = await prisma.post.findMany({
 orderBy: { createdAt: 'desc' },
 take: 10,
 });

 return { posts };
 };
 // src/routes/posts/+page.svelte
 import type { PageData } from './$types';

 export let data: PageData;
 Recent Posts
 {#each data.posts as post}

 {post.title}
 {post.createdAt.toLocaleDateString()}

 {/each}

3) Form with Server Action
 Language: typescript
 Code:

 // src/routes/create/+page.server.ts
 import type { Actions } from './$types';
 import { fail } from '@sveltejs/kit';
 import { z } from 'zod';
 const schema = z.object({
 title: z.string().min(3),
 content: z.string().min(10),
 });
 export const actions: Actions = {
 create: async ({ request }) => {
 const formData = await request.formData();
 const data = {
 title: formData.get('title'),
 content: formData.get('content'),
 };

 const result = schema.safeParse(data);
 if (!result.success) {
 return fail(, {
 errors: result.error.flatten().fieldErrors,
 data,
 });
 }

 // Save to database
 // await prisma.post.create({ data: result.data });

 return { success: true };
 },
 };
 // src/routes/create/+page.svelte
 import { enhance } from '$app/forms';
 import type { ActionData } from './$types';

 export let form: ActionData;

 Title

 {#if form?.errors?.title}
 {form.errors.title[0]}
 {/if}

 Content
 {form?.data?.content ?? ''}
 {#if form?.errors?.content}
 {form.errors.content[0]}
 {/if}

 Create Post

 {#if form?.success}
 Post created successfully!
 {/if}

4) Writable Store with Persistence
 Language: typescript
 Code:

 // src/lib/stores/cart.ts
 import { writable } from 'svelte/store';
 import { browser } from '$app/environment';
 type CartItem = { id: string; name: string; quantity: number };
 function createCartStore() {
 // Load from localStorage if in browser
 const stored = browser ? localStorage.getItem('cart') : null;
 const initial: CartItem[] = stored ? JSON.parse(stored) : [];

 const { subscribe, set, update } = writable(initial);

 // Persist to localStorage on changes
 if (browser) {
 subscribe((value) => {
 localStorage.setItem('cart', JSON.stringify(value));
 });
 }

 return {
 subscribe,
 add: (item: CartItem) => update((cart) => {
 const existing = cart.find((i) => i.id === item.id);
 if (existing) {
 existing.quantity += item.quantity;
 return [...cart];
 }
 return [...cart, item];
 }),
 remove: (id: string) => update((cart) => cart.filter((i) => i.id !== id)),
 clear: () => set([]),
 };
 }
 export const cart = createCartStore();
 // Usage in component:
 //
 // import { cart } from '$lib/stores/cart';
 // $: total = $cart.reduce((sum, item) => sum + item.quantity, 0);
 //
 // Cart: {total} items

TECHNICAL DETAILS
Documentation: https://kit.svelte.dev/


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Source: Claude Pro Directory
Website: https://claudepro.directory
URL: https://claudepro.directory/skills/svelte-sveltekit-fullstack

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