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Mark

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Show Dev: The Zero-Budget AI Marketing Stack That Earns While I Sleep

#ai #productivity #showdev #webdev

Been building this for 3 weeks. Here's the honest technical breakdown.

What I Built

A fully automated marketing company run by AI agents:

  • CalcFuel — 20+ free marketing calculators (top-of-funnel)
  • A $19 AI prompt pack — sold via Stripe, auto-delivered via webhook
  • Email opt-in funnel — MailerLite list building from calculator pages
  • Bluesky/Mastodon auto-posts — cron jobs push tool updates to social

All orchestrated by Claude AI agents running on Paperclip with zero human code written.

The Stack (All Free Tiers)

Layer Tool Cost
Frontend Next.js + Vercel $0
Email MailerLite $0
Payments Stripe 2.9% + 30¢ per sale
AI agents Claude via Paperclip Monthly
Analytics Vercel Analytics + GA4 $0
Social Bluesky API, Mastodon API $0

The only real cost is the Claude API usage for the agents themselves.

The Automated Funnel Flow 

Visitor lands on CalcFuel calculator
  → Runs a free calculation
  → Sees email opt-in CTA ("Get your full marketing checklist")
  → Joins MailerLite list (opted-in)
  → Receives welcome sequence (AI-authored)
  → Welcome email links to $19 prompt pack
  → Stripe checkout → webhook fires
  → PDF delivered automatically within 30 seconds
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Zero manual steps. I could be asleep and it all works.

The Part That Surprised Me

The Stripe webhook auto-delivery was surprisingly simple:

// app/api/stripe-webhook/route.ts
export async function POST(req: Request) {
  const event = stripe.webhooks.constructEvent(body, sig, secret);

  if (event.type === "checkout.session.completed") {
    const session = event.data.object;
    const email = session.customer_details.email;

    // Generate personalized marketing plan with Claude
    const plan = await generateMarketingPlan(session.metadata);

    // Send delivery email with PDF + plan
    await sendDeliveryEmail(email, plan);
  }
}
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The customer gets their download before they've even left the "thank you" page.

What Actually Drives Traffic

The free calculators on CalcFuel are the real traffic engine. Tools like:

People searching for "calculate marketing ROI" land on the free tool, get value immediately, and see the email opt-in. No ad spend. Pure SEO + organic.

The AI Agent Architecture

The agents run on a 15-minute heartbeat:

  1. Check inbox — any new Paperclip tasks assigned?
  2. Execute — code, deploy, write content, post to social
  3. Update status — comment on the issue with results
  4. Exit — no persistent state between runs

Each agent is a fresh Claude context. Shared memory lives in markdown files that every agent reads on startup. It's surprisingly robust.

The Hard Numbers

  • Calculators built: 35+
  • Dev.to articles published: 13
  • Bluesky posts: 5
  • Mastodon posts: 5
  • Email opt-ins: still growing
  • Revenue: working on it 🙃

The goal is $200 AUD by May 18. We're running the experiment in public.

Lessons Learned

What worked:

  • Free tools as top-of-funnel convert better than cold content
  • Automated social posting keeps the presence alive even during "off" hours
  • Stripe webhooks + Claude = surprisingly good auto-fulfillment

What didn't:

  • Twitter/X API is dead for free tier (402 CreditsDepleted on every call)
  • Reddit new app registration is blocked for everyone now (Nov 2025 change)
  • Sending too many similar articles to Dev.to tanks your account reach

The surprising insight: AI agents are great at building things but need very specific instructions to do the right thing. The challenge isn't the technical capability — it's the governance (making sure agents don't violate spam laws, run up costs, or build the wrong thing).

The Code

CalcFuel is on GitHub: getmarketingai-byte/calcfuel

Fair warning: it was written by AI agents, so the code quality is... AI-agent quality.

Try the Tools

Happy to answer questions about the agent setup in the comments.

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