Cloudflare Workers Frameworks

Workers Frameworks Integration

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

Quick Start: Choose Your Framework

| Framework | Best For | SSR | Static | Workers Native |

|-----------|----------|-----|--------|----------------|

| Hono | APIs, lightweight apps | ✅ | ✅ | ✅ Native |

| Remix | Full-stack apps | ✅ | ✅ | ✅ Adapter |

| Next.js | React apps | ✅ | ✅ | ⚠️ OpenNext |

| Astro | Content sites | ✅ | ✅ | ✅ Adapter |

| SvelteKit | Svelte apps | ✅ | ✅ | ✅ Adapter |

| Qwik | Resumable apps | ✅ | ✅ | ✅ Adapter |

| Nuxt | Vue apps | ✅ | ✅ | ✅ Nitro |

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

| Error | Framework | Cause | Solution |

|-------|-----------|-------|----------|

| No matching export "default" | All | Wrong export format | Use export default app not module.exports |

| Worker exceeded CPU limit | Next.js | Heavy SSR | Use ISR, reduce bundle size |

| Cannot read properties of undefined (reading 'env') | Remix | Missing context | Pass context to loader/action |

| globalThis is not defined | All | Node.js globals | Use nodejs_compat flag |

| Dynamic require not supported | All | CJS in ESM | Convert to ESM imports |

| Response body is locked | All | Body already read | Clone response before reading |

| Bindings not available | All | Missing wrangler config | Add bindings to wrangler.jsonc |

| 404 on static assets | All | Wrong assets config | Configure assets in wrangler.jsonc |

| Hydration mismatch | React/Vue | Server/client differ | Ensure consistent rendering |

| Maximum call stack exceeded | All | Circular imports | Refactor module structure |

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:

| Reference | Load When |

|-----------|-----------|

| references/hono.md | Building APIs, microservices, or lightweight apps |

| references/remix.md | Full-stack React with loaders/actions |

| references/nextjs.md | Next.js App Router on Workers via OpenNext |

| references/astro.md | Content sites, blogs, docs, marketing pages |

| references/sveltekit.md | Svelte applications on Workers |

| references/qwik.md | Resumable apps, instant loading |

| references/nuxt.md | Vue 3 applications with Nitro |

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

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

See Also

• workers-performance - Optimization techniques
• workers-runtime-apis - Workers APIs reference
• cloudflare-worker-base - Basic Workers setup