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

> Source: <https://dev.to/justsosdsds/-zero-cost-ai-agent-stack-cloudflare-workers-gemini-web-247-free-ai-2fke>
> Published: 2026-06-06 07:54:18+00:00

*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.*