A German developer quit his corporate job and grew a simple habit tracker app to $15K in monthly recurring revenue
Sebastian built HabitKit in Flutter, uses Cursor as his AI coding editor, and grew through building in public and App Store optimization.
Subject: HabitKit (Sebastian)Freemium mobile habit tracking app with subscriptions
Case Overview & Background
Sebastian, 32 and living in Germany, quit his corporate programming job in 2022 to become a full-time indie app developer. He built HabitKit, a clean habit tracker with a tile-based grid chart, with all data stored on the device and no sign-in. He says it ranks in the top five for habit tracker in several countries.
How AI Is Used
Step-by-Step Process
The first version only tracked habits and showed progress.
He shared development progress on social media.
He ranks for important keywords like habit tracker.
Customer Acquisition & Distribution
Limitations, Risks & Failure Modes
What may not apply to you, and what could go wrong:
- The figures are self-reported and were not independently checked
- AI plays a supporting role, not the core of the business
- Habit trackers are a crowded category
Key Takeaways
- App Store search can be a durable free channel
- AI coding tools speed up a solo developer's work
Sources
Starter Story: How I Built It: $15K/Month Mobile App
Note: Video interview with transcript. States the 15,000 MRR figure, downloads and his use of Cursor.
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