Replit Changed Everything — My First AI-Powered Apps

How an AI-powered coding platform turned a non-developer into a serial app builder

In Part 1 of this series, I talked about how I discovered low-code through Retool — and the addictive feeling of building something myself for the first time. But Retool had limits. It was designed for internal tools, not consumer products. I wanted more.

Then I found Replit. And everything accelerated.

The Replit Moment

For those who haven’t used it: Replit is an online coding environment with AI built in. You describe what you want, and the AI writes code. You can see the result instantly. You iterate, adjust, deploy — all from your browser. No local setup, no DevOps, no deployment headaches.

Coming from Retool’s drag-and-drop world, Replit felt like removing the training wheels. Suddenly, I wasn’t limited to pre-built components. I could build anything — and the AI would handle the parts I couldn’t code myself.

The learning curve was real. I went from „drag this button here“ to „we need a React component that handles state.“ But because the AI translated my business logic into code, I could focus on what I wanted to build rather than how to write it.

The Experimentation Phase

What followed was a burst of creative energy. Every problem I encountered — at work, in my personal life, in my community — became a potential app. Some were practical. Some were ambitious. All of them taught me something.

Here’s what I built in those first few months on Replit:

🇪🇺 VIES API — EU VAT Validation

My first „real“ Replit project was born from actual work frustration. If you’ve ever had to validate European VAT identification numbers, you know the pain: the official EU VIES system is clunky, slow, and offers zero API usability.

I built a clean web interface that connects to the official EU Commission database, validates VAT IDs across all 27 member states, and returns company information. Simple? Yes. Useful? Incredibly. This was the first time I built something that other people could use immediately — not just an internal dashboard, but a tool with a real interface and real utility.

📈 Micro-Cap Trading System

This one was ambitious — maybe too ambitious. I built an AI-powered micro-cap stock trading system that pulls Reddit sentiment data, connects to CapTrader, and covers markets from the US and Europe to Japan, China, and Africa.

Did it make me rich? No. But it taught me about API integration, real-time data processing, and building complex multi-region applications. It also taught me a humbling lesson: just because you can build something doesn’t mean you should. More on that in the final article of this series.

💡 Business Konzept Generator

This one came from a conversation with a friend who had „a million ideas“ but never wrote any of them down. I built an app where you describe a business idea — even by voice — and it generates a structured business concept with market analysis, competitive landscape, and a feasibility score.

It was the first time I used AI not just to build the app, but as a core feature inside the app. The meta-level was not lost on me: AI helped me build a tool that uses AI to help others.

⚓ Maritime Logbuch

This one was personal. I’m a boat owner — my houseboat „Wilma“ lives in a marina on the Rhine. And if you’ve ever kept a maritime logbook, you know it’s still mostly pen-and-paper in 2026.

I built a digital ship’s logbook with voice input, AI-powered analysis, and crew management. You can dictate your log entry while at the helm, and the AI structures it properly — weather conditions, navigation data, crew notes, everything.

This project planted the seed for something much bigger. But we’ll get to Marina Master in a later article.

🥬 Schiersteiner Wochenmarkt — When Vibe-Coding Meets Community

This might be the project I’m most proud of, even though it’s not the most technically impressive.

I live in Wiesbaden-Schierstein, a neighborhood on the Rhine with a beautiful harbor promenade. In 2023, a group of passionate locals — myself included — founded the „Interessengemeinschaft Schiersteiner Wochenmarkt e.V.“ to bring a weekly farmers‘ market to our community. Within a year, we had over 200 members. I became one of the Marktmeister — the people who organize and run the market every week.

Running a volunteer-driven farmers‘ market sounds simple until you try it. You need to manage vendors, coordinate volunteer shifts, communicate with members, handle events (we also organize Dine en Blanc, a Christmas market, and a Glühweintreff), and keep the whole operation running on zero budget and pure enthusiasm.

So I built them an app.

The Schiersteiner Wochenmarkt platform handles member management, vendor coordination, event planning, volunteer scheduling, and news updates. It replaced a chaos of WhatsApp groups, Excel sheets, and email chains with a single, clean interface.

This is what I mean when I say I’m not just building „tech demos.“ This app runs a real community organization. Volunteers use it every week. New members sign up through it. And I built it — a Marktmeister with no coding degree — because the need was there and I had the tools.

This is what vibe-coding unlocks. Not just the ability to build products for profit — but the power to solve real problems for the people around you.

What I Learned From the Replit Phase

Looking back, this period taught me five critical things:

1. Speed matters more than perfection.

None of these apps were architecturally beautiful. Some had rough edges. But they worked, and they shipped fast. In the time it would have taken to write a requirements document, I had a working prototype.

2. Real problems make the best teachers.

I learned more about databases from building the Wochenmarkt membership system than from any tutorial. When your neighbor can’t log in, you fix authentication fast.

3. AI-assisted coding is a conversation, not a command.

The best results came from iterating with the AI — not from one-shot prompts. „Make this button blue“ is a command. „The user needs to feel confident clicking this — how should we design the flow?“ is a conversation.

4. The portfolio effect is real.

Each project made the next one faster. Not because I was memorizing syntax, but because I was developing architectural intuition. After the third app, I could feel when a design decision was wrong.

5. Non-developers see problems differently.

And that’s an advantage. I wasn’t trying to write elegant code. I was trying to solve problems I actually had. That focus on utility over craftsmanship led to apps that were immediately useful — even if a professional developer would rewrite 80% of the code.

The Limits of Replit — And What Came Next

Replit was transformative. But as my ambitions grew, I started hitting walls. Performance constraints. Limited server-side capabilities. The feeling that I was building real products on a platform designed for prototypes.

I needed more power. More control. More… vibe.

That’s when I discovered Claude Desktop and, later, Claude Code. And that’s when things got truly serious.

This is Part 2 of a 7-part series about my journey from zero coding experience to building production applications with AI. In Part 3, I’ll deep-dive into CalendarGenie and Post-er — the first products I built that people actually pay for.

Try what I’ve built:

• 🧞 [CalendarGenie](https://calendargenie.replit.app) — Turn any screenshot into calendar events
• ✍️ [Post-er](https://post-er.replit.app) — AI-powered content creation
• ⚡ [Energy Backbone](https://energy-backbone.bigdataheaven-software.de) — Smart energy management
• ⚓ [Marina Master](https://marina-master.bigdataheaven-software.de) — AI-powered marina management
• 🥬 [Schiersteiner Wochenmarkt](https://schiersteinerwochenmarkt.de) — Our community market

Andreas Kulpa is Executive Director of Product Management at CRIF and a vibe-coder based in Wiesbaden, Germany. When he’s not building software, he’s running a farmers‘ market on the Rhine. Connect with him on [LinkedIn](https://linkedin.com/in/akulpa).