I Built a SaaS Overnight That Replaces $15K Agencies (Full Breakdown)

Six hours ago, this did not exist. Now it's a SaaS that does what agencies charge $15K and 8 weeks for.

I can't code. Never shipped a SaaS by myself. Claude Code did the heavy lifting. I just said what I wanted. Here's every decision, what worked, and the mistake that almost cost me 4 hours.

The Problem That Started This Claude Code ruined my life. Not because it's bad. Because now I have too many ideas. Two weeks ago, I couldn't build anything without my developer’s help. Now I can validate in hours, not weeks. So I built a market research tool.

Why market research? Because if you don't establish a good avatar and know your market, all your other elements aren't going to work. You might be working in a market with no money, or not talking properly to your avatar. The alternatives suck: •ChatGPT → generic garbage •Do it yourself → 40+ hours •Agency → $15K and 8 weeks

I posted an X article about the concept. Almost 350K+ impressions.  People kept asking: "I only want the market research part." That was the signal.

How I Built It Overnight The Stack: •Claude Code (with Opus 4.5) •Rife Loop (7 autonomous loops) •PRD Document A few weeks ago I didn't know what any of this meant either.

PRD = Product Requirement Document. Problem definition + user flow + feature requirements. You build it with any AI. Rife Loop = The game changer. Old way: Ask AI to build → it sends back code → you test → find bug → send back → repeat forever. New way: It builds → tests itself → if broken, fixes itself → moves to next checklist item → repeats until done. That's why I launched Claude Code before going to sleep. Terrible advice by the way. I woke up at 3 AM like a kid on Christmas wondering if it worked.

The Mistake That Cost Me 2 Hours I wanted to test locally first. Bad idea. To test locally, I had to set up Supabase locally. Database configuration. Email validation from localhost. Never done it before. Nightmare. The fix? Deploy directly. GitHub + Vercel + Supabase. All free. Claude set it all up.

The build kept failing because I had the wrong Supabase key from my local testing disaster. Fix: Vercel → Settings → Environment Variables → Add the keys Supabase gives you. If you avoid this one mistake, you save 4 hours.

The Real Test I tested it with a friend who runs B2B outreach. He had a client: Switzerland B2B SaaS, high ticket (around six figures per customer). We ran the market research through my tool. His words: "The result was amazing."

Now he wants to buy the tool so he can send this research to all his prospects, so they'll want to talk with him. If you find someone who understands your market deeply, you have a gold mine.

What I Learned I don't want to give you the vibe that vibe-coding has no bugs. It has bugs. But every time I build something new, I have fewer bugs than before. Pro tip: I always run two or three instances of Claude Code at the same time.

Different results. I can pick and choose. One version had a landing page. But this version worked the best. I had so much fun building this. It helped some friends with their business. It's going to help me massively for all the tools and apps I want to build. You don't need to code. You don't need an expensive degree. You need a problem worth solving and the patience to let AI do what AI does best. That's it. No magic.