Cloudflare Worker Builder

Scaffold a working Cloudflare Worker project from a brief description. Produces a deployable project with Hono routing, Vite dev server, and Static Assets.

Workflow

Step 1: Understand the Project

Ask about the project to choose the right bindings and structure:

• What does the app do? (API only, SPA + API, landing page)

• What data storage? (D1 database, R2 files, KV cache, none)

• Auth needed? (Clerk, better-auth, none)

• Custom domain or workers.dev subdomain?

A brief like "todo app with database" is enough to proceed.

Step 2: Scaffold the Project

npm create cloudflare@latest my-worker -- --type hello-world --ts --git --deploy false --framework none cd my-worker npm install hono npm install -D @cloudflare/vite-plugin vite

Copy and customise the asset files from this skill's assets/ directory:

• wrangler.jsonc — Worker configuration

• vite.config.ts — Vite + Cloudflare plugin

• src/index.ts — Hono app with Static Assets fallback

• package.json — Scripts and dependencies

• tsconfig.json — TypeScript config

• public/index.html — SPA entry point

Step 3: Configure Bindings

Add bindings to wrangler.jsonc based on project needs. Wrangler 4.45+ auto-provisions resources on first deploy — always specify explicit names:

{ "name": "my-worker", "main": "src/index.ts", "compatibility_date": "2025-11-11", "assets": { "directory": "./public/", "binding": "ASSETS", "not_found_handling": "single-page-application", "run_worker_first": ["/api/*"] }, // Add as needed: "d1_databases": [{ "binding": "DB", "database_name": "my-app-db" }], "r2_buckets": [{ "binding": "STORAGE", "bucket_name": "my-app-files" }], "kv_namespaces": [{ "binding": "CACHE", "title": "my-app-cache" }] }

Step 4: Deploy

npm run dev # Local dev at http://localhost:8787 wrangler deploy # Production deploy

Critical Patterns

Export Syntax

// CORRECT — use this pattern export default app

// WRONG — causes "Cannot read properties of undefined" export default { fetch: app.fetch }

Source: honojs/hono #3955

Static Assets + API Routes

Without run_worker_first , SPA fallback intercepts API routes and returns index.html instead of JSON:

"assets": { "not_found_handling": "single-page-application", "run_worker_first": ["/api/*"] // CRITICAL }

Source: workers-sdk #8879

Vite Config

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

export default defineConfig({ plugins: [cloudflare()] })

Always set the main field in wrangler.jsonc — the Vite plugin needs it.

Scheduled/Cron Handlers

When adding cron triggers, switch to explicit export:

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

Reference Files

Read these for detailed troubleshooting:

• references/common-issues.md — 10 documented issues with sources and fixes

• references/architecture.md — Route priority, caching, Workers RPC

• references/deployment.md — CI/CD, auto-provisioning, gradual rollouts