/cloudflare-workers

name: cloudflare-workers
description: Rapid development with Cloudflare Workers - build and deploy serverless applications on Cloudflare's global network. Use when building APIs, full-stack web apps, edge functions, background jobs, or real-time applications. Triggers on phrases like "cloudflare workers", "wrangler", "edge computing", "serverless cloudflare", "workers bindings", or files like wrangler.toml, worker.ts, worker.js.
metadata:
  version: "3.1.2"
  openclaw:
    homepage: https://github.com/tenequm/skills/tree/main/skills/cloudflare-workers
    emoji: "☁️"
    primaryEnv: CLOUDFLARE_API_TOKEN
    envVars:
      - name: CLOUDFLARE_API_TOKEN
        required: false
        description: Cloudflare API token (scoped). Used by wrangler for non-interactive auth and CI deploys.
      - name: CLOUDFLARE_ACCOUNT_ID
        required: false
        description: Cloudflare account ID, set as a CI secret for wrangler deploys.

Cloudflare Workers

Overview

Cloudflare Workers is a serverless execution environment that runs JavaScript, TypeScript, Python, and Rust code on Cloudflare's global network. Workers execute in milliseconds, scale automatically, and integrate with Cloudflare's storage and compute products through bindings.

**Key Benefits:**

• **Zero cold starts** - Workers run in V8 isolates, not containers
• **Global deployment** - Code runs in 300+ cities worldwide
• **Rich ecosystem** - Bindings to D1, KV, R2, Durable Objects, Queues, Containers, Workflows, and more
• **Full-stack capable** - Build APIs and serve static assets in one project
• **Standards-based** - Uses Web APIs (fetch, crypto, streams, WebSockets)

When to Use This Skill

Use Cloudflare Workers for:

• **APIs and backends** - RESTful APIs, GraphQL, tRPC, WebSocket servers
• **Full-stack applications** - React, Next.js, Remix, Astro, Vue, Svelte with static assets
• **Edge middleware** - Authentication, rate limiting, A/B testing, routing
• **Background processing** - Scheduled jobs (cron), queue consumers, webhooks
• **Data transformation** - ETL pipelines, real-time data processing
• **AI applications** - RAG systems, chatbots, image generation with Workers AI
• **Durable workflows** - Multi-step long-running tasks with automatic retries (Workflows)
• **Container workloads** - Run Docker containers alongside Workers (Containers)
• **MCP servers** - Host remote Model Context Protocol servers
• **Proxy and gateway** - API gateways, content transformation, protocol translation

Quick Start Workflow

1. Install Wrangler CLI

npm install -g wrangler

# Login to Cloudflare
wrangler login

2. Create a New Worker

# Using C3 (create-cloudflare) - recommended
npm create cloudflare@latest my-worker

# Or create manually
wrangler init my-worker
cd my-worker

3. Write Your Worker

**Basic HTTP API (TypeScript):**

export default {
  async fetch(request: Request, env: Env): Promise<Response> {
    const url = new URL(request.url);

    if (url.pathname === "/api/hello") {
      return Response.json({ message: "Hello from Workers!" });
    }

    return new Response("Not found", { status: 404 });
  },
};

**With environment variables and KV:**

interface Env {
  MY_VAR: string;
  MY_KV: KVNamespace;
}

export default {
  async fetch(request: Request, env: Env): Promise<Response> {
    // Access environment variable
    const greeting = env.MY_VAR;

    // Read from KV
    const value = await env.MY_KV.get("my-key");

    return Response.json({ greeting, value });
  },
};

4. Develop Locally

# Start local development server with hot reload
wrangler dev

# Access at http://localhost:8787

5. Deploy to Production

# Deploy to workers.dev subdomain
wrangler deploy

# Deploy to custom domain (configure in wrangler.toml)
wrangler deploy

Core Concepts

Workers Runtime

Workers use the V8 JavaScript engine with Web Standard APIs:

• **Execution model**: Isolates (not containers) - instant cold starts
• **CPU time limit**: 10ms (Free), 30s (Paid) per request
• **Memory limit**: 128 MB per isolate
• **Languages**: JavaScript, TypeScript, Python, Rust
• **APIs**: fetch, crypto, streams, WebSockets, WebAssembly

**Supported APIs:**

• Fetch API (HTTP requests)
• URL API (URL parsing)
• Web Crypto (encryption, hashing)
• Streams API (data streaming)
• WebSockets (real-time communication)
• Cache API (edge caching)
• HTML Rewriter (HTML transformation)

Handlers

Workers respond to events through handlers:

**Fetch Handler** (HTTP requests):

export default {
  async fetch(request: Request, env: Env, ctx: ExecutionContext) {
    return new Response("Hello!");
  },
};

**Scheduled Handler** (cron jobs):

export default {
  async scheduled(event: ScheduledEvent, env: Env, ctx: ExecutionContext) {
    // Runs on schedule defined in wrangler.toml
    await env.MY_KV.put("last-run", new Date().toISOString());
  },
};

**Queue Handler** (message processing):

export default {
  async queue(batch: MessageBatch<any>, env: Env, ctx: ExecutionContext) {
    for (const message of batch.messages) {
      await processMessage(message.body);
      message.ack();
    }
  },
};

Bindings

Bindings connect your Worker to Cloudflare resources. Configure in `wrangler.toml`:

**KV (Key-Value Storage):**

[[kv_namespaces]]
binding = "MY_KV"
id = "your-kv-namespace-id"

// Usage
await env.MY_KV.put("key", "value");
const value = await env.MY_KV.get("key");

**D1 (SQL Database):**

[[d1_databases]]
binding = "DB"
database_name = "my-database"
database_id = "your-database-id"

// Usage
const result = await env.DB.prepare(
  "SELECT * FROM users WHERE id = ?"
).bind(userId).all();

**R2 (Object Storage):**

[[r2_buckets]]
binding = "MY_BUCKET"
bucket_name = "my-bucket"

// Usage
await env.MY_BUC