Workers Frameworks Integration

Build full-stack applications on Cloudflare Workers using modern frameworks.

Quick Start: Choose Your Framework

Framework Decision Tree

Need an API only?
  └─ Yes → Hono (fastest, smallest)
  └─ No → Building a full app?
           └─ React → Next.js (OpenNext) or Remix
           └─ Vue → Nuxt
           └─ Svelte → SvelteKit
           └─ Content-heavy → Astro
           └─ Max performance → Qwik

Top 10 Framework Errors

No matching export "default"

export default app

module.exports

Worker exceeded CPU limit

Cannot read properties of undefined (reading 'env')

context

globalThis is not defined

nodejs_compat

Dynamic require not supported

Response body is locked

Bindings not available

404 on static assets

assets

Hydration mismatch

Maximum call stack exceeded

Hono Quick Start (Recommended)

// src/index.ts
import { Hono } from 'hono';
import { cors } from 'hono/cors';
import { logger } from 'hono/logger';

interface Env {
  DB: D1Database;
  KV: KVNamespace;
}

const app = new Hono<{ Bindings: Env }>();

// Middleware
app.use('*', logger());
app.use('/api/*', cors());

// Routes
app.get('/', (c) => c.text('Hello Workers!'));

app.get('/api/users', async (c) => {
  const { results } = await c.env.DB.prepare('SELECT * FROM users').all();
  return c.json(results);
});

app.post('/api/users', async (c) => {
  const { name, email } = await c.req.json();
  await c.env.DB.prepare('INSERT INTO users (name, email) VALUES (?, ?)')
    .bind(name, email)
    .run();
  return c.json({ success: true }, 201);
});

export default app;

// wrangler.jsonc
{
  "name": "my-app",
  "main": "src/index.ts",
  "compatibility_date": "2024-12-01",
  "compatibility_flags": ["nodejs_compat"],
  "d1_databases": [
    { "binding": "DB", "database_name": "my-db", "database_id": "xxx" }
  ]
}

Static Assets Configuration

// wrangler.jsonc - Serving static files
{
  "name": "my-app",
  "main": "src/index.ts",
  "assets": {
    "directory": "./public",
    "binding": "ASSETS"
  }
}

// Serve static with fallback to app
import { Hono } from 'hono';

const app = new Hono<{ Bindings: { ASSETS: Fetcher } }>();

// API routes
app.get('/api/*', apiHandler);

// Static assets fallback
app.get('*', async (c) => {
  return c.env.ASSETS.fetch(c.req.raw);
});

export default app;

When to Load References

Load the specific framework reference when user:

references/hono.md

references/remix.md

references/nextjs.md

references/astro.md

references/sveltekit.md

references/qwik.md

references/nuxt.md

Common Patterns Across Frameworks

Environment Bindings Access

// Hono
app.get('/', (c) => c.env.DB.prepare('...'));

// Remix
export async function loader({ context }) {
  return context.cloudflare.env.DB.prepare('...');
}

// Astro
const db = Astro.locals.runtime.env.DB;

// SvelteKit
export async function load({ platform }) {
  return platform.env.DB.prepare('...');
}

// Nuxt
const { cloudflare } = useRuntimeConfig();
// Or via nitro: event.context.cloudflare.env.DB

Error Handling Pattern

// Universal error boundary pattern
app.onError((err, c) => {
  console.error(`[${c.req.path}] ${err.message}`);

  if (err instanceof HTTPException) {
    return err.getResponse();
  }

  return c.json(
    { error: 'Internal Server Error' },
    500
  );
});

Performance Tips

1. Bundle Size: Keep under 1MB compressed
2. Cold Starts: Minimize top-level code
3. Streaming: Use streaming SSR when available
4. Caching: Leverage Cache API and CDN
5. Code Splitting: Dynamic imports for routes

See Also

• workers-performance

  - Optimization techniques

• workers-runtime-apis

  - Workers APIs reference

• cloudflare-worker-base

  - Basic Workers setup