Deploying SvelteKit

SvelteKit uses adapters to transform your app for different deployment targets. You pick an adapter, run npm run build, and get output tailored for that platform.

How Adapters Work

The build process has two steps:

1. Svelte compiles components to JavaScript
2. The adapter transforms the output for the target platform

npm run build
          ↓
  SvelteKit build
          ↓
   Adapter transform
          ↓
  Platform-specific output

Vercel (Recommended for Most Projects)

npm install -D @sveltejs/adapter-vercel

Push to GitHub and connect the repo on vercel.com. Zero additional configuration needed — Vercel detects SvelteKit automatically.

Node.js Server

For self-hosted deployments:

npm install -D @sveltejs/adapter-node

Build and run:

npm run build
node build/index.js  # starts an Express-like server on PORT (default 3000)

Set the PORT environment variable to change the port.

Cloudflare Pages / Workers

npm install -D @sveltejs/adapter-cloudflare

Your app runs at the edge in Cloudflare's global network. Use platform.env to access KV, D1, R2, and other Cloudflare bindings from your load functions and API routes.

Static Site (No Server)

For fully static sites (no server-side rendering):

npm install -D @sveltejs/adapter-static

Every page must be prerenderable — no server-only code, no +page.server.js with dynamic logic.

Mark pages for prerendering:

// +page.js or +layout.js
export const prerender = true;

Or enable it globally in svelte.config.js:

Environment Variables

SvelteKit splits env vars into public and private:

# .env
SECRET_DB_URL=postgres://...      # server only
PUBLIC_API_URL=https://api.mysite.com  # safe to expose

Using $env/static/* gives you build-time type checking — typos in env var names are caught before deployment.

Deployment Checklist

Adapter Comparison