name	cloudflare-worker-base
description	Production-tested setup for Cloudflare Workers with Hono, Vite, and Static Assets. Use when: creating new Cloudflare Workers projects, setting up Hono routing with Workers, configuring Vite plugin for Workers, adding Static Assets to Workers, deploying with Wrangler, or encountering deployment errors, routing conflicts, or HMR crashes. Prevents 6 documented issues: export syntax errors, Static Assets routing conflicts, scheduled handler errors, HMR race conditions, upload race conditions, and Service Worker format confusion. Keywords: Cloudflare Workers, CF Workers, Hono, wrangler, Vite, Static Assets, @cloudflare/vite-plugin, wrangler.jsonc, ES Module, run_worker_first, SPA fallback, API routes, serverless, edge computing, "Cannot read properties of undefined", "Static Assets 404", "A hanging Promise was canceled", "Handler does not export", deployment fails, routing not working, HMR crashes
license	MIT

Cloudflare Worker Base Stack

Production-tested: cloudflare-worker-base-test (https://cloudflare-worker-base-test.webfonts.workers.dev) Last Updated: 2025-10-20 Status: Production Ready ✅

Quick Start (5 Minutes)

1. Scaffold Project

npm create cloudflare@latest my-worker -- \
  --type hello-world \
  --ts \
  --git \
  --deploy false \
  --framework none

Why these flags:

--type hello-world: Clean starting point
--ts: TypeScript support
--git: Initialize git repo
--deploy false: Don't deploy yet (configure first)
--framework none: We'll add Vite ourselves

2. Install Dependencies

cd my-worker
npm install hono@4.10.1
npm install -D @cloudflare/vite-plugin@1.13.13 vite@latest

Version Notes:

hono@4.10.1: Latest stable (verified 2025-10-20)
@cloudflare/vite-plugin@1.13.13: Latest stable, fixes HMR race condition
vite: Latest version compatible with Cloudflare plugin

3. Configure Wrangler

Create or update wrangler.jsonc:

{
  "$schema": "node_modules/wrangler/config-schema.json",
  "name": "my-worker",
  "main": "src/index.ts",
  "account_id": "YOUR_ACCOUNT_ID",
  "compatibility_date": "2025-10-11",
  "observability": {
    "enabled": true
  },
  "assets": {
    "directory": "./public/",
    "binding": "ASSETS",
    "not_found_handling": "single-page-application",
    "run_worker_first": ["/api/*"]
  }
}

CRITICAL: run_worker_first Configuration

Without this, SPA fallback intercepts API routes
API routes return index.html instead of JSON
Source: workers-sdk #8879

4. Configure Vite

Create vite.config.ts:

import { defineConfig } from 'vite'
import { cloudflare } from '@cloudflare/vite-plugin'

export default defineConfig({
  plugins: [
    cloudflare({
      // Optional: Configure the plugin if needed
    }),
  ],
})

Why @cloudflare/vite-plugin:

Official plugin from Cloudflare
Supports HMR with Workers
Enables local development with Miniflare
Version 1.13.13 fixes "A hanging Promise was canceled" error

The Four-Step Setup Process

Step 1: Create Hono App with API Routes

Create src/index.ts:

/**
 * Cloudflare Worker with Hono
 *
 * CRITICAL: Export pattern to prevent build errors
 * ✅ CORRECT: export default app
 * ❌ WRONG:   export default { fetch: app.fetch }
 */

import { Hono } from 'hono'

// Type-safe environment bindings
type Bindings = {
  ASSETS: Fetcher
}

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

/**
 * API Routes
 * Handled BEFORE static assets due to run_worker_first config
 */
app.get('/api/hello', (c) => {
  return c.json({
    message: 'Hello from Cloudflare Workers!',
    timestamp: new Date().toISOString(),
  })
})

app.get('/api/health', (c) => {
  return c.json({
    status: 'ok',
    version: '1.0.0',
    environment: c.env ? 'production' : 'development',
  })
})

/**
 * Fallback to Static Assets
 * Any route not matched above is served from public/ directory
 */
app.all('*', (c) => {
  return c.env.ASSETS.fetch(c.req.raw)
})

/**
 * Export the Hono app directly (ES Module format)
 * This is the correct pattern for Cloudflare Workers with Hono + Vite
 */
export default app

Why This Export Pattern:

Source: honojs/hono #3955
Using { fetch: app.fetch } causes: "Cannot read properties of undefined (reading 'map')"

Exception: If you need scheduled/tail handlers, use Module Worker format:

export default {
  fetch: app.fetch,
  scheduled: async (event, env, ctx) => { /* ... */ }
}

Step 2: Create Static Frontend

Create public/index.html:

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>My Worker App</title>
  <link rel="stylesheet" href="/styles.css">
</head>
<body>
  <div class="container">
    <h1>Cloudflare Worker + Static Assets</h1>
    <button onclick="testAPI()">Test API</button>
    <pre id="output"></pre>
  </div>
  <script src="/script.js"></script>
</body>
</html>

Create public/script.js:

async function testAPI() {
  const response = await fetch('/api/hello')
  const data = await response.json()
  document.getElementById('output').textContent = JSON.stringify(data, null, 2)
}

Create public/styles.css:

body {
  font-family: system-ui, -apple-system, sans-serif;
  max-width: 800px;
  margin: 40px auto;
  padding: 20px;
}

button {
  background: #0070f3;
  color: white;
  border: none;
  padding: 12px 24px;
  border-radius: 6px;
  cursor: pointer;
}

pre {
  background: #f5f5f5;
  padding: 16px;
  border-radius: 6px;
  overflow-x: auto;
}

Step 3: Update Package Scripts

Update package.json:

{
  "scripts": {
    "dev": "wrangler dev",
    "deploy": "wrangler deploy",
    "cf-typegen": "wrangler types"
  }
}

Step 4: Test & Deploy

# Generate TypeScript types for bindings
npm run cf-typegen

# Start local dev server (http://localhost:8787)
npm run dev

# Deploy to production
npm run deploy

Known Issues Prevention

This skill prevents 6 documented issues:

Issue #1: Export Syntax Error

Error: "Cannot read properties of undefined (reading 'map')" Source: honojs/hono #3955 Prevention: Use export default app (NOT { fetch: app.fetch })

Issue #2: Static Assets Routing Conflicts

Error: API routes return index.html instead of JSON Source: workers-sdk #8879 Prevention: Add "run_worker_first": ["/api/*"] to wrangler.jsonc

Issue #3: Scheduled/Cron Not Exported

Error: "Handler does not export a scheduled() function" Source: honojs/vite-plugins #275 Prevention: Use Module Worker format when needed:

export default {
  fetch: app.fetch,
  scheduled: async (event, env, ctx) => { /* ... */ }
}

Issue #4: HMR Race Condition

Error: "A hanging Promise was canceled" during development Source: workers-sdk #9518 Prevention: Use @cloudflare/vite-plugin@1.13.13 or later

Issue #5: Static Assets Upload Race

Error: Non-deterministic deployment failures in CI/CD Source: workers-sdk #7555 Prevention: Use Wrangler 4.x+ with retry logic (fixed in recent versions)

Issue #6: Service Worker Format Confusion

Error: Using deprecated Service Worker format Source: Cloudflare migration guide Prevention: Always use ES Module format (shown in Step 1)

Configuration Files Reference

wrangler.jsonc (Full Example)

{
  "$schema": "node_modules/wrangler/config-schema.json",
  "name": "my-worker",
  "main": "src/index.ts",
  "account_id": "YOUR_ACCOUNT_ID",
  "compatibility_date": "2025-10-11",
  "observability": {
    "enabled": true
  },
  "assets": {
    "directory": "./public/",
    "binding": "ASSETS",
    "not_found_handling": "single-page-application",
    "run_worker_first": ["/api/*"]
  }
  /* Optional: Environment Variables */
  // "vars": { "MY_VARIABLE": "production_value" }

  /* Optional: KV Namespace Bindings */
  // "kv_namespaces": [
  //   { "binding": "MY_KV", "id": "YOUR_KV_ID" }
  // ]

  /* Optional: D1 Database Bindings */
  // "d1_databases": [
  //   { "binding": "DB", "database_name": "my-db", "database_id": "YOUR_DB_ID" }
  // ]

  /* Optional: R2 Bucket Bindings */
  // "r2_buckets": [
  //   { "binding": "MY_BUCKET", "bucket_name": "my-bucket" }
  // ]
}

Why wrangler.jsonc over wrangler.toml:

JSON format preferred since Wrangler v3.91.0
Better IDE support with JSON schema
Comments allowed with JSONC

vite.config.ts (Full Example)

import { defineConfig } from 'vite'
import { cloudflare } from '@cloudflare/vite-plugin'

export default defineConfig({
  plugins: [
    cloudflare({
      // Persist state between HMR updates
      persist: true,
    }),
  ],

  // Optional: Configure server
  server: {
    port: 8787,
  },

  // Optional: Build optimizations
  build: {
    target: 'esnext',
    minify: true,
  },
})

tsconfig.json

{
  "compilerOptions": {
    "target": "ES2022",
    "module": "ES2022",
    "lib": ["ES2022"],
    "moduleResolution": "bundler",
    "types": ["@cloudflare/workers-types/2023-07-01"],
    "resolveJsonModule": true,
    "allowJs": true,
    "checkJs": false,
    "strict": true,
    "esModuleInterop": true,
    "skipLibCheck": true,
    "forceConsistentCasingInFileNames": true,
    "isolatedModules": true,
    "noEmit": true
  },
  "include": ["src/**/*"],
  "exclude": ["node_modules"]
}

API Route Patterns

Basic JSON Response

app.get('/api/users', (c) => {
  return c.json({
    users: [
      { id: 1, name: 'Alice' },
      { id: 2, name: 'Bob' }
    ]
  })
})

POST with Request Body

app.post('/api/users', async (c) => {
  const body = await c.req.json()

  // Validate and process body
  return c.json({ success: true, data: body }, 201)
})

Route Parameters

app.get('/api/users/:id', (c) => {
  const id = c.req.param('id')
  return c.json({ id, name: 'User' })
})

Query Parameters

app.get('/api/search', (c) => {
  const query = c.req.query('q')
  return c.json({ query, results: [] })
})

Error Handling

app.get('/api/data', async (c) => {
  try {
    // Your logic here
    return c.json({ success: true })
  } catch (error) {
    return c.json({ error: error.message }, 500)
  }
})

Using Bindings (KV, D1, R2)

type Bindings = {
  ASSETS: Fetcher
  MY_KV: KVNamespace
  DB: D1Database
  MY_BUCKET: R2Bucket
}

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

app.get('/api/data', async (c) => {
  // KV
  const value = await c.env.MY_KV.get('key')

  // D1
  const result = await c.env.DB.prepare('SELECT * FROM users').all()

  // R2
  const object = await c.env.MY_BUCKET.get('file.txt')

  return c.json({ value, result, object })
})

Static Assets Best Practices

Directory Structure

public/
├── index.html          # Main entry point
├── styles.css          # Global styles
├── script.js           # Client-side JavaScript
├── favicon.ico         # Favicon
└── assets/             # Images, fonts, etc.
    ├── logo.png
    └── fonts/

SPA Fallback

The "not_found_handling": "single-page-application" configuration means:

Unknown routes return index.html
Useful for React Router, Vue Router, etc.
BUT requires run_worker_first for API routes!

Route Priority

With "run_worker_first": ["/api/*"]:

/api/hello → Worker handles it (returns JSON)
/ → Static Assets serve index.html
/styles.css → Static Assets serve styles.css
/unknown → Static Assets serve index.html (SPA fallback)

Caching Static Assets

Static Assets are automatically cached at the edge. To bust cache:

<link rel="stylesheet" href="/styles.css?v=1.0.0">
<script src="/script.js?v=1.0.0"></script>

Development Workflow

Local Development

npm run dev

Server runs on http://localhost:8787
HMR enabled (file changes reload automatically)
Uses Miniflare for local simulation
All bindings work locally (KV, D1, R2)

Testing API Routes

# Test GET endpoint
curl http://localhost:8787/api/hello

# Test POST endpoint
curl -X POST http://localhost:8787/api/echo \
  -H "Content-Type: application/json" \
  -d '{"test": "data"}'

Type Generation

npm run cf-typegen

Generates worker-configuration.d.ts with:

Binding types (KV, D1, R2, etc.)
Environment variable types
Auto-completes in your editor

Deployment

# Deploy to production
npm run deploy

# Deploy to specific environment
wrangler deploy --env staging

# Tail logs in production
wrangler tail

# Check deployment status
wrangler deployments list

Complete Setup Checklist

Project scaffolded with npm create cloudflare@latest
Dependencies installed: hono@4.10.1, @cloudflare/vite-plugin@1.13.13
wrangler.jsonc created with:
- account_id set to your Cloudflare account
- assets.directory pointing to ./public/
- assets.run_worker_first includes /api/*
- compatibility_date set to recent date
vite.config.ts created with @cloudflare/vite-plugin
src/index.ts created with Hono app
- Uses export default app (NOT { fetch: app.fetch })
- Includes ASSETS binding type
- Has fallback route: app.all('*', (c) => c.env.ASSETS.fetch(c.req.raw))
public/ directory created with static files
npm run cf-typegen executed successfully
npm run dev starts without errors
API routes tested in browser/curl
Static assets serve correctly
HMR works without crashes
Ready to deploy with npm run deploy

Advanced Topics

Adding Middleware

import { Hono } from 'hono'
import { logger } from 'hono/logger'
import { cors } from 'hono/cors'

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

// Global middleware
app.use('*', logger())
app.use('/api/*', cors())

// Route-specific middleware
app.use('/admin/*', async (c, next) => {
  // Auth check
  await next()
})

Environment-Specific Configuration

// wrangler.jsonc
{
  "name": "my-worker",
  "env": {
    "staging": {
      "vars": { "ENV": "staging" }
    },
    "production": {
      "vars": { "ENV": "production" }
    }
  }
}

Deploy: wrangler deploy --env staging

Custom Error Pages

app.onError((err, c) => {
  console.error(err)
  return c.json({ error: 'Internal Server Error' }, 500)
})

app.notFound((c) => {
  return c.json({ error: 'Not Found' }, 404)
})

Testing with Vitest

npm install -D vitest @cloudflare/vitest-pool-workers

Create vitest.config.ts:

import { defineConfig } from 'vitest/config'

export default defineConfig({
  test: {
    poolOptions: {
      workers: {
        wrangler: { configPath: './wrangler.jsonc' },
      },
    },
  },
})

See reference/testing.md for complete testing guide.

File Templates

All templates are available in the templates/ directory:

wrangler.jsonc - Complete Worker configuration
vite.config.ts - Vite + Cloudflare plugin setup
package.json - Dependencies and scripts
tsconfig.json - TypeScript configuration
src/index.ts - Hono app with API routes
public/index.html - Static frontend example
public/styles.css - Example styling
public/script.js - API test functions

Copy these files to your project and customize as needed.

Reference Documentation

For deeper understanding, see:

architecture.md - Deep dive into export patterns, routing, and Static Assets
common-issues.md - All 6 issues with detailed troubleshooting
deployment.md - Wrangler commands, CI/CD patterns, and production tips

Official Documentation

Cloudflare Workers: https://developers.cloudflare.com/workers/
Static Assets: https://developers.cloudflare.com/workers/static-assets/
Vite Plugin: https://developers.cloudflare.com/workers/vite-plugin/
Wrangler Configuration: https://developers.cloudflare.com/workers/wrangler/configuration/
Hono: https://hono.dev/docs/getting-started/cloudflare-workers
Context7 Library ID: /websites/developers_cloudflare-workers

Dependencies (Latest Verified 2025-10-20)

{
  "dependencies": {
    "hono": "^4.10.1"
  },
  "devDependencies": {
    "@cloudflare/vite-plugin": "^1.13.13",
    "@cloudflare/workers-types": "^4.20251011.0",
    "vite": "^7.0.0",
    "wrangler": "^4.43.0",
    "typescript": "^5.9.0"
  }
}

Production Example

This skill is based on the cloudflare-worker-base-test project:

Live: https://cloudflare-worker-base-test.webfonts.workers.dev
Build Time: ~45 minutes (actual)
Errors: 0 (all 6 known issues prevented)
Validation: ✅ Local dev, HMR, production deployment all successful

All patterns in this skill have been validated in production.

Questions? Issues?

Check reference/common-issues.md first
Verify all steps in the 4-step setup process
Ensure export default app (not { fetch: app.fetch })
Ensure run_worker_first is configured
Check official docs: https://developers.cloudflare.com/workers/

Install Skill

SKILL.md