Deploy to Cloudflare with adapter-cloudflare

SvelteKit’s Cloudflare adapter outputs a Worker that runs your SSR routes on workerd and serves prerendered/static assets alongside it.

Install and configure

npm i -D @sveltejs/adapter-cloudflare

Kit 3 keeps config in the Vite plugin options (see Kit 3 Changes):

// vite.config.js
import adapter from '@sveltejs/adapter-cloudflare';
import { sveltekit } from '@sveltejs/kit/vite';
import { defineConfig } from 'vite';

export default defineConfig({
    plugins: [
        sveltekit({
            adapter: adapter({
                config: undefined,          // path to wrangler config, if non-default
                platformProxy: {            // bindings in dev via wrangler proxy
                    configPath: undefined,
                    environment: undefined,
                    persist: undefined,
                },
                fallback: 'plaintext',      // SPA fallback mode for non-prerendered routes
                routes: {
                    include: ['/*'],
                    exclude: ['<all>'],     // static assets win over SSR
                },
            }),
        }),
    ],
});

What the adapter gives you

• Bindings: access KV, R2, D1, Durable Objects through event.platform.env in load functions and endpoints
• platformProxy: during vite dev, bindings are proxied from your wrangler config so dev behaves like prod (Miniflare-backed)
• Routes split: include/exclude decide which requests hit the Worker vs static assets; <all> exclusion keeps asset serving fast
• Deploy: wrangler deploy after vite build

Gotcha: runtime is workerd, not Node. Node-only dependencies fail at deploy even if dev works. Check the Cloudflare frameworks topic for the runtime constraints.

When to prefer this over adapter-node

• Your target is Cloudflare’s network (edge SSR, no servers to run)
• Your app uses Cloudflare storage primitives directly
• You want the cheapest always-on hosting for spiky traffic

For a self-hosted Docker lane (the lab default for apps), use adapter-node instead. For a comparison of every framework on Cloudflare, see the frameworks landscape.