How a Solo Developer Built a $15K/Month Habit Tracker (And How You Can Too)

Hey there,

Ever feel like building a successful app requires a team, a big budget, or VC funding?

Meet Sebastian Ro, a solo indie developer from Germany who quietly built Habit Kit—a minimalist habit-tracking app that now earns $15,000/month with 300,000+ downloads.

• No employees

• No investors

• Just smart execution

Here's how he did it—and what you can learn from his journey.

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1. The Unsexy (But Brilliant) MVP

Sebastian didn't overcomplicate it. His MVP had two core features:

• A clean, tile-based grid to track habits

• Local data storage (no sign-in required)

Why it worked:

🔒 Privacy-first: Users loved that their data stayed on their devices
⚡ Speed: Built in just 2 months using Flutter (one codebase for iOS + Android)
🎯 Focus: No bloat—just habit tracking + progress visualization

Lesson: Solve one problem exceptionally well.

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2. The Growth Hack You're Ignoring: ASO

Most founders obsess over ads. Sebastian mastered App Store Optimization (ASO) instead:

• Placed "habit tracker" at the start of his app name (keyword gold)

• Optimized every pixel: screenshots, subtitles, metadata

• Asked for reviews at the perfect moment (right after a user's first habit check-off)

Result: Thousands of 5-star reviews → higher rankings → organic downloads for free.

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3. The $100/Month "Cheat Code"

Sebastian's only paid growth lever? Apple Search Ads—with a $100/month budget.

Why?

• Signals to Apple that his app is valuable (boosting organic rankings)

• Low-cost way to test keywords

Takeaway: You don't need a big ad spend—just strategic bets.

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4. Building in Public = Free Marketing

While others built in stealth, Sebastian shared his journey openly:

• Posted wins (and failures) on Twitter, LinkedIn, and Threads

• Attracted podcast features and indie dev collabs

• Turned followers into early users and evangelists

Lesson: Visibility compounds. Share your process.

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5. The Indie Developer's Mindset

Sebastian's advice for aspiring founders:

1. "Just start building": Your idea will evolve as you go

2. Solve your own problems: You're your first customer

3. Quit (temporarily): He took a sabbatical to focus—then doubled down

"You can compete with big companies if you optimize your app store presence and deliver high-quality UX."

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The Bottom Line

Sebastian's story proves you don't need:

• A team

• A complex app

• A massive budget

You just need:
✅ A simple, focused product
✅ Smart ASO + organic growth
✅ The guts to ship and share

Question for you: What's the smallest version of your idea you could build in 2 months?

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P.S. Want the exact tools Sebastian uses? Here's his stack:

💬 Liked this deep dive? Share your thoughts in comments!

(Inspired by Starter Story’s YouTube interview with Pat)