Claude + Cloudflare Workers

Overview

Running Claude on Cloudflare Workers enables building AI-powered applications that deploy globally with zero cold starts. The Anthropic SDK works in the Workers runtime, allowing you to call Claude’s API from edge locations closest to your users.

While Claude API latency is typically the bottleneck (not network latency), Workers provide benefits for AI applications: instant startup, global deployment, and access to Cloudflare’s storage services (KV for caching, D1 for conversation history, R2 for file storage).

Streaming is particularly valuable in this setup: you can stream Claude’s response directly to the client through the Worker, providing real-time output without buffering.

When to Use

Use Claude + Cloudflare Workers for AI-powered APIs and applications that need global edge deployment. It is ideal for AI chatbots, content generation endpoints, and any Claude-powered service that benefits from Cloudflare’s ecosystem.

Getting Started

npm create cloudflare@latest claude-worker
cd claude-worker
npm install @anthropic-ai/sdk

import Anthropic from '@anthropic-ai/sdk'

export default {
  async fetch(request: Request, env: Env) {
    const client = new Anthropic({ apiKey: env.ANTHROPIC_API_KEY })
    const message = await client.messages.create({
      model: 'claude-sonnet-4-5-20250929',
      max_tokens: 1024,
      messages: [{ role: 'user', content: 'Hello from the edge!' }]
    })
    return Response.json(message)
  }
}