Zero-Cost AI Agent Stack: Cloudflare Workers + Gemini Web = 24/7 Free AI

A developer built a fully autonomous AI agent that runs at zero monthly cost by combining Cloudflare Workers' free tier with Google Gemini's free web interface. The stack uses Chrome DevTools Protocol to control a browser that interacts with gemini.google.com, translating standard OpenAI-compatible API requests into browser actions. For a photography studio deployment, the agent reduced customer response time from 2-6 hours to instant, eliminated overnight missed inquiries, and cut owner time spent on FAQs from 3 hours to 30 minutes daily.

I built a fully autonomous AI agent that costs $0/month to run. Here is exactly how. When you build an AI agent, the first thing you reach for is an API: OpenAI, DeepSeek, Groq. They work great — until you check the bill. Even at $0.14/million tokens, a moderately active agent burns through $30-50/month. That is a GPU you will never save up for. The second problem: most conversations do not need a frontier model . When a customer asks "How much is wedding photography?", you do not need GPT-5. You need a FAQ lookup + a friendly reply. Yet API pricing charges the same rate whether you are writing a novel or answering "What are your hours?" I wanted something better. So I hacked together a stack that runs completely free : Cloudflare Workers free tier → Gemini Web free → 24/7 AI Agent Here is the architecture and how you can build your own. Google Gemini's web interface at gemini.google.com is free. No API key, no rate limits, no token counting. The model is powerful enough for 90% of customer service tasks. The catch: it is a web page, not an API. But we can fix that. Workers free tier gives you 100,000 requests/day. That is more than enough for a small business AI agent handling ~500 customer chats daily. We use Chrome DevTools Protocol CDP to control a browser that talks to Gemini Web. A small Node.js proxy translates standard OpenAI-compatible API requests into browser actions. Customer Message ↓ Cloudflare Worker /api/chat ↓ Node.js Proxy :57322 ↓ Chrome CDP → types into gemini.google.com ↓ Extracts reply → returns as API response This is the core — a server that accepts OpenAI-format requests and forwards them to Gemini Web via Playwright: js const { chromium } = require "playwright" ; async function getGeminiReply prompt { const browser = await chromium.connectOverCDP "http://127.0.0.1:9222" ; const page = browser.contexts 0 .pages .find p = p.url .includes "gemini" ; // Type and send const tb = page.getByRole "textbox", { name: /enter a prompt/i } .first ; await tb.fill prompt ; await page.getByRole "button", { name: /send message/i } .click ; // Wait for completion for let i = 0; i < 80; i++ { await page.waitForTimeout 1000 ; const hasStop = await page.evaluate = document.querySelector ' aria-label="Stop generating" ' ; if hasStop break; } // Extract and return return await page.evaluate = { const msgs = document.querySelectorAll "message-content" ; return msgs msgs.length - 1 ?.innerText || ""; } ; } Not every question needs Gemini. FAQ matching handles 70% of queries instantly and for free: js const FAQ = { keywords: "价格", "多少钱" , a: "基础套餐 ¥1999 起..." }, { keywords: "预约", "档期" , a: "提前3-7天预约即可..." }, { keywords: "地址", "哪里" , a: "我们在成都锦江区..." } ; function matchFAQ message { for const item of FAQ { if item.keywords.some k = message.includes k { return item.a; // Instant, no API call } } return null; // Fall through to Gemini } The Worker also stores customer contacts in Cloudflare KV: async function handleLead request, env { const { name, contact, need } = await request.json ; await env.LEADS.put crypto.randomUUID , JSON.stringify { name, contact, need, created at: new Date .toISOString } ; return Response.json { ok: true } ; } I deployed this for a photography studio in 2 hours. Here is what happened: | Metric | Before | After | |---|---|---| | Customer response time | 2-6 hours | Instant | | Missed inquiries overnight | ~40% | 0% | | Owner time spent on FAQs | 3h/day | 30min/day | | Monthly cost | ¥0 owner's labor | ¥0 fully free | The live demo is at: https://ihug-demo.wigginsbuck7.workers.dev/ The agent stack is now free: Codex Desktop → Router :57323 → < 4000 tokens → Gemini Web FREE → ≥ 4000 tokens → DeepSeek API paid, but rare Info Pipeline → GitHub API + Hacker News + Dev.to all free Cloudflare KV → Lead storage free tier Chrome CDP → Browser automation free Total monthly spend: ¥0 plus ~¥15 for DeepSeek on long replies, maybe ¥30/month . --remote-debugging-port=9222 The entire setup takes one afternoon. After that, it runs indefinitely at zero cost. If you found this useful, the demo is live at ihug-demo.wigginsbuck7.workers.dev. Drop a test inquiry — an AI will answer you, and it costs me nothing.