I built two Etsy SEO tools in 14 days — full stack breakdown (Cloudflare Workers + KV + Stripe)

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I built two Etsy SEO tools in 14 days — full stack breakdown

I spent the last two weeks building two products targeting the 5M+ Etsy seller market. Here's the honest story — what worked, what didn't, and the full technical stack.

The problem

Most Etsy sellers write listings from a maker's perspective. They describe what they made. Buyers search for what they want to find.

"Handmade ceramic mug, blue, 12oz" gets almost no search traffic.

"Handmade Ceramic Coffee Mug | Blue Stoneware 12oz | Gift for Coffee Lovers" ranks for a dozen buyer searches.

Same product. One gets found. One doesn't.

What I built

ContentBase — AI listing optimizer. Paste any Etsy, Shopify, or Amazon listing. Get a rewritten title, description, and 13 keyword-targeted tags in ~10 seconds. Free for 5/day, no signup. Pro is $9/month.

→ contentbase-crw.pages.dev

ShopScan — on-demand Etsy SEO audit. Pay $19, submit your listing, get a 12-page report (score, keyword gaps, full rewrite, action plan) by email within 24h.

→ shopscan-eff.pages.dev

The stack — all free tier

Cloudflare Workers — API layer, keeps Anthropic key server-side
Cloudflare KV — rate limiting + Pro token storage
Cloudflare Pages — static frontend
Brevo — transactional email (300/day free)
Stripe Payment Links — no checkout page to build

Total monthly infrastructure cost: $0.

Pro activation without webhooks

Most people implement Stripe webhooks for post-payment activation. I found a simpler pattern.

After payment, Stripe redirects to:

https://contentbase-crw.pages.dev?session_id={CHECKOUT_SESSION_ID}

The frontend POSTs the session_id to /activate-pro on the Worker. The Worker validates the format (cs_live_ prefix — unguessable), generates a token, stores in KV, emails via Brevo.

No webhook endpoint. No signing secret. No HTTPS concerns. Works perfectly.

async function handleActivatePro(request, env) {
  const { session_id, email } = await request.json();

  if (!session_id?.startsWith('cs_live_')) {
    return json({ error: 'Invalid session' }, 400);
  }

  // Prevent replay attacks
  const existing = await env.CB_TOKENS.get(`session:${session_id}`);
  if (existing) return json({ token: existing, reused: true });

  const token = generateToken();
  await env.CB_TOKENS.put(`token:${token}`, 'active');
  await env.CB_TOKENS.put(`session:${session_id}`, token);

  await sendEmail(env, { to: email, subject: 'Your ContentBase Pro access is live' });
  return json({ token, success: true });
}

Rate limiting with Cloudflare KV

No database needed:

async function checkRateLimit(ip, env) {
  const key = `rate:${ip}:${new Date().toISOString().split('T')[0]}`;
  const count = parseInt(await env.CB_RATE.get(key) || '0');
  if (count >= 5) return { allowed: false };
  await env.CB_RATE.put(key, String(count + 1), { expirationTtl: 86400 });
  return { allowed: true };
}

Keys expire after 24h automatically. Cleanup is free.

What I learned

Cloudflare is absurdly good for this use case. Worker + KV + Pages covers serverless functions, key-value storage, and static hosting — all free, globally distributed.

Zero-friction free tier matters. No email required to use ContentBase. No account. Just paste and get. The conversion to Pro happens after people see the output.

Distribution is harder than building. The technical side took days. Finding actual Etsy sellers to try it is taking weeks. If you've solved Etsy/niche community distribution, I'd genuinely love to hear how.