How a solo developer grew a habit tracker to $15K MRR

Executive overview

Most indie app developers burn through their runway without finding traction. Sebastian Röhl quit his corporate job with no idea, struggled for six months, went back to work, and eventually scaled HabitKit to $15,000 MRR as a solo developer.

The path was not a clean arc. He treated App Store Optimization as his primary growth lever and combined it with deliberate build-in-public content to bootstrap organic reach at near-zero cost.

Ranking for high-volume App Store keywords is a sustainable, low-cost acquisition engine that outcompetes larger budgets.

The founding path

• Quit corporate programming job in 2022 with 12 months of runway and no concrete idea
• Built HabitKit — a tile-based grid habit tracker — in two months using Flutter
• All data stored locally, no sign-in required; privacy by design from day one
• First six months: fewer than a dozen downloads; returned to old job after deadline
• Reached $3K MRR by end of 2023; quit again permanently at the start of 2024
• Crossed $15K MRR by end of 2024 with 300,000+ downloads and 2,000+ reviews

App Store Optimization (ASO)

• ASO — editing metadata (keywords, app name, subtitle, screenshots) to rank in search results — was the biggest growth driver
• Placed the target keyword "Habit Tracker" at the very start of the app name
• Used Astro for keyword research to assess popularity and ranking difficulty
• Triggered the native review prompt immediately after the user's first successful habit check-off — their first win moment — to maximise five-star conversion
• Reviews and ratings compound: volume drives ranking; ranking drives downloads

Building in public

• Shared development screenshots on X, LinkedIn, Bluesky, and Threads before launch
• Early positive reception accelerated the decision to ship quickly
• Authentic content — wins and failures — led to podcast guest spots, video features, and developer network connections

Paid acquisition strategy

• Ran Apple Search Ads at $100/month — minimal spend, used as a potential algorithmic signal that Apple favours active advertisers
• AppFigures used for app analytics, marketing data, and supplementary keyword research

Finding and validating ideas

• Build anything first; good ideas surface naturally once you are in motion
• Solve your own problems — being your own first customer clarifies requirements without external validation overhead

Stack and costs

• Flutter (cross-platform iOS/Android from a single codebase) — core development framework
• Cursor — AI-powered IDE for autocomplete and problem-solving
• RevenueCat — subscription and purchase management; 1% of revenue; biggest single expense
• Total costs outside RevenueCat: ~$200–$300/month
• Operating margin is very high; no employees, no infrastructure overhead

Key lesson

• Organic App Store ranking removes the need for a large marketing budget
• Competing with well-funded apps is possible if you secure top-five placement on high-traffic keywords
• Quitting the job was the prerequisite: eight hours of client work left no capacity for independent development