---
name: sveltekit-e07044154c67
description: Expert SvelteKit assistance covering file-based routing (+page.svelte, +page.server.ts), form actions, hooks, and adapters. Use when developing full-stack, server-rendered Svelte web applications.
---

# SvelteKit

SvelteKit is the meta-framework for Svelte, similar to Next.js for React. It uses standard Web APIs and provides routing, server-side rendering, and API endpoints.

## When to Use

- **Svelte Apps**: The standard framework for building full-stack Svelte applications.
- **Full Stack**: Unified backend and frontend.
- **Edge Deployment**: Runs on any platform via Adapters (Vercel, Cloudflare, Netlify, Node).

## Quick Start

File-based routing in `src/routes`.

```svelte
<!-- src/routes/+page.svelte -->
<script>
  let { data } = $props(); // Received from +page.server.js
</script>

<h1>{data.title}</h1>
```

```javascript
// src/routes/+page.server.js
export function load() {
  return { title: "Hello from Server" };
}
```

## Core Concepts

### Load Functions

`load` functions in `+page.server.js` run before the page renders, fetching data. The data is typed automatically in the component.

### Form Actions

Handle form submissions in `+page.server.js` exports named `actions`.

```javascript
export const actions = {
  default: async ({ request }) => {
    const data = await request.formData();
    // save to db
  },
};
```

### Adapters

Deployment targets are plugins. `adapter-auto`, `adapter-node`, `adapter-cloudflare`.

## Common Patterns

### Form Actions with Progressive Enhancement

**Problem**: Writing separate API endpoints and client fetch handlers for simple form submissions.

**Solution**:
Use SvelteKit Form Actions with `use:enhance`:

```typescript
// src/routes/login/+page.server.ts
import { fail, redirect, type Actions } from "@sveltejs/kit";

export const actions: Actions = {
  default: async ({ request }) => {
    const data = await request.formData();
    const email = data.get("email");
    if (!email) return fail(400, { email, missing: true });
    // Process login
    throw redirect(303, "/dashboard");
  },
};
```

```svelte
<!-- src/routes/login/+page.svelte -->
<script>
  import { enhance } from '$app/forms';
  export let form;
</script>

<form method="POST" use:enhance>
  <input name="email" value={form?.email ?? ''} />
  <button type="submit">Log In</button>
</form>
```

## Best Practices

**Do**:

- Use Svelte 5 Runes: SvelteKit 2+ fully supports Runes mode.
- Use `App.State`: New SvelteKit interface for typesafe global app state.
- Stream Data: Return promises in `load` functions to stream non-critical data.

**Don't**:

- Use `store` for server data: Use `page.data` (Context) for data passing down the tree to avoid state leakage on valid server execution.
- Perform sensitive database queries or secret token lookups in client-facing `+page.ts` files; place them in `+page.server.ts` instead.

## Troubleshooting

| Error                                               | Cause                                                         | Solution                                                                    |
| :-------------------------------------------------- | :------------------------------------------------------------ | :-------------------------------------------------------------------------- |
| `500 Internal Error: Cannot load module ... in SSR` | Client-only library imported directly in SSR bundle.          | Use dynamic import in `onMount()` or check `browser` in `$app/environment`. |
| `Not found: /route`                                 | File naming convention mismatch.                              | Ensure route page is named `+page.svelte` (with leading plus sign).         |
| `Adapter not specified`                             | `svelte.config.js` missing build adapter for target platform. | Install and configure `@sveltejs/adapter-auto` or `@sveltejs/adapter-node`. |

## References

- [SvelteKit Documentation](https://kit.svelte.dev/)


---
Source attribution: G1Joshi
Original project: https://github.com/G1Joshi/Agent-Skills/blob/6a74cf03a8a86dc7d993ead3091b41123dbd0181/skills/frameworks/sveltekit/SKILL.md
License: MIT
License information: https://opensource.org/license/mit
Original upstream instructions; downloaded from Mega AI Hub.

## Upstream license notice

MIT License

Copyright (c) 2026 G1Joshi

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.



# Mega AI Hub resource metadata

Creator / publisher: G1Joshi
Original project: https://github.com/G1Joshi/Agent-Skills/blob/6a74cf03a8a86dc7d993ead3091b41123dbd0181/skills/frameworks/sveltekit/SKILL.md
Attribution basis: Source repository record

Fields of work: Development & Engineering, Product Management
Roles: Frontend Developer, Full-Stack Developer, Product Manager
Specialties: Backend, Cross Platform, Frontend
Tools: Netlify, Vercel
Country applicability: Country not specified
Classification basis: Source catalog labels
Instruction SHA-256: 0e7bb76dce2fec2d7ceba80cd60b7fd359108cfefaef9a38a1fdaa659782b3b6