How it works

<script src="https://challenges.cloudflare.com/turnstile/v0/api.js" defer></script>
<div class="cf-turnstile" data-sitekey="YOUR_SITEKEY"></div>

const r = await fetch('https://challenges.cloudflare.com/turnstile/v0/siteverify', {
  method: 'POST',
  body: new URLSearchParams({ secret: env.TURNSTILE_SECRET, response: token }),
}).then((res) => res.json());

if (!r.success) return new Response('Blocked', { status: 403 });

Security → Bots → "Block AI bots" / "Pay per crawl"
One toggle. Cloudflare maintains the crawler signatures for you.

const ua = request.headers.get('user-agent') || '';
const bot = classifyAiCrawler(ua); // GPTBot, ClaudeBot, CCBot, PerplexityBot…

if (bot?.policy === 'block')   return new Response('Forbidden', { status: 403 });
if (bot?.policy === 'license') return new Response('Payment required', { status: 402 });
return fetch(request); // humans pass straight through

const country = request.cf.country;          // free, at the edge
const eu = ['DE', 'FR', 'IE', 'NL' /* …EEA */];
const db = eu.includes(country) ? env.RESIDENCY_EU : env.RESIDENCY_US;

await db.prepare('INSERT INTO records (data) VALUES (?)').bind(payload).run();

"d1_databases": [
  { "binding": "RESIDENCY_EU", "database_name": "app-eu" }, // created --jurisdiction eu (guaranteed EU)
  { "binding": "RESIDENCY_US", "database_name": "app-us" }  //         --location enam (US placement hint)
]

AI → AI Search → New
Data source: your R2 bucket or uploaded docs
Cloudflare chunks, embeds, and indexes them for you.

const res = await env.AI.autorag('your-instance').aiSearch({
  query: question,
});

return Response.json({ answer: res.response, citations: res.data });

"ratelimits": [
  { "name": "STAMPEDE_LIMITER", "namespace_id": "1001",
    "simple": { "limit": 5, "period": 10 } }
]

const ip = request.headers.get('CF-Connecting-IP') ?? 'anon';
const { success } = await env.STAMPEDE_LIMITER.limit({ key: ip });
if (!success) return new Response('Slow down', { status: 429 });

const cache = caches.default;
let res = await cache.match(request);          // HIT?
if (!res) {
  res = await renderExpensive();               // MISS: pay once
  res.headers.set('Cache-Control', 'public, max-age=60');
  ctx.waitUntil(cache.put(request, res.clone()));
}
return res;

const { meta } = await env.DB.prepare(
  'UPDATE stock SET qty = qty - 1 WHERE id = ?1 AND qty > 0'
).bind(productId).run();

const bought = meta.changes === 1;   // 0 changes = sold out, no oversell

const localHour = ((sendHourUtc + r.tz_offset) % 24 + 24) % 24;
let decision;
if (!r.opted_in)                            decision = 'blocked';    // no consent (TCPA)
else if (localHour < 8 || localHour >= 21)  decision = 'suppressed'; // quiet hours
else                                        decision = 'sent';

await env.DISPATCH_DB.prepare(
  'INSERT INTO dispatch_audit (id, batch_id, recipient_id, decision, reason, created_at) VALUES (?, ?, ?, ?, ?, ?)'
).bind(id, batchId, r.recipient_id, decision, reason, new Date().toISOString()).run();
// rows are only ever inserted, never updated or deleted

const r = await env.AI.run('@cf/meta/llama-3.3-70b-instruct-fp8-fast', {
  messages: [{ role: 'system', content: COWBOY_PROMPT }, { role: 'user', content: 'Tell me a joke.' }],
});

const audio = await env.AI.run('@cf/deepgram/aura-2-en', { text, speaker: 'zeus' });
// baked to /cowboy/jokes/<id>-zeus-<line>.mp3 -> served static, no per-use spend

await env.LEADERBOARD_DB
  .prepare('INSERT INTO leaderboard_scores (name, score, ip_hash, ts) VALUES (?, ?, ?, ?)')
  .bind(name, score, ipHash, ts).run();

const ipHash = await sha256(request.headers.get('CF-Connecting-IP')); // never store raw IP
const recent = await db.prepare('SELECT COUNT(*) c FROM leaderboard_scores WHERE ip_hash=? AND ts>?')
  .bind(ipHash, Date.now() - 60_000).first();
if (recent.c >= 8) return json({ ok: false, error: 'rate limited' }, 429);