How building in public got my habit-tracking mobile app to $15k/mo

After a false start, Sebastian Röhl, 31, found success with a simple, visually appealing habit-tracking app called HabitKit.

He credits building in public and App Store optimization with explosive growth. Less than two years in and he's netting $15,000 a month in MRR and lifetime licenses.

Here's how he did it 👇.

Taking the leap

A strong desire for creative freedom and dissatisfaction with a traditional career drove my journey into indie hacking.

I stumbled upon the Indie Hackers podcast while studying computer science at university and it was a real eye-opener for me. It made me realize I could create something of my own to support my lifestyle and give me the freedom to work on projects I’m passionate about.

My degree laid the foundation for my technical skills in software development. I’m basically self-taught when it comes to mobile app development.

I worked as a software engineer for three years after graduating, mostly dealing with web and cloud software development.

I decided to take a leap of faith in 2022 and quit my job to fully commit to developing my own apps.

They didn’t grow fast enough to sustain my lifestyle, and I had to go back to my old job in April 2023.

But later that year, my second app — HabitKit — grew so much that I was able to quit my job again. I’ve worked full-time on my own apps since February 2024.

A false start

I built my first app, Liftbear, to suit my workout needs after struggling to find an existing app that wasn't complex and bloated. I still use it on a daily basis.

I built it using Flutter, a framework that allows you to develop apps for both iOS and Android with a single codebase.

It was my first serious attempt at creating a mobile app, so it involved a lot of trial and error. After launching it in 2022, I spent roughly six months refining the user interface and adding new features.

But it didn’t quite take off as I’d hoped.

It gained some users and received positive feedback, but it didn’t generate significant revenue or a large user base. I still consider it a success as it taught me important lessons about app development and marketing.

Habit tracking

I launched HabitKit in November 2022. The idea came from a personal desire to improve my daily habits and track my progress in a visually appealing way.

I wanted a habit tracker that could display my consistency in a grid format, similar to GitHub’s contribution graph.

It's also built in Flutter. It’s an offline-only app, so data is stored on a user’s device and it doesn’t need a backend.

It was fairly basic when it launched. But as it gained traction, user feedback started pouring in and I accumulated a huge backlog of cool new features.

I’ve added features like notifications, interactive home screen widgets, new view modes, streaks and more. I’m currently working on the ninth big content update.

The app has a freemium model, where users can access basic features for free and pay to unlock premium features. Users can subscribe monthly or annually to the Pro plan, or buy a “lifetime” license.

It’s currently making about $7,800 in MRR and about $7,300 a month in lifetime purchases.

Building in public

Building in public on Twitter/X has been by far the most successful way I've grown and marketed my apps.

 I’ve built a community around my products by sharing development updates, screenshots, and insights from my indie hacking journey.

Engaging with other indie hackers and responding to user feedback on the platform has increased visibility and driven downloads.

The Twitter/X community has also been incredibly supportive, providing valuable feedback and helping to spread the word about my apps.

I also spent time optimizing my app listings on the App Store and Google Play. By carefully researching and selecting relevant keywords for my apps, I’ve improved the discoverability of my apps.

Nowadays, ~98% of my new users find my apps directly on the App Store or Google Play.

But not all my marketing efforts have worked. I tried to market HabitKit and Liftbear on Instagram for a couple of months. But I quickly lost motivation and dropped it.

It’s super important that you find a marketing strategy that you can do long-term. 

Keep it simple

I’ve intentionally kept my apps simple and focused on solving very specific problems.

HabitKit isn’t trying to be the most feature-packed habit tracker out there. It’s designed to do one thing exceptionally well: visually track habits using a grid format.

This simplicity has resonated with users who are looking for a clean, straightforward tool.

I think other indie hackers can take inspiration from this. Sometimes, doing less can actually lead to more success.

Prepare for uncertainty

When you’re building a product on your own, there’s always some kind of doubt about whether it will gain traction or resonate with users.

This uncertainty can be super exhausting, especially when you’ve poured countless hours into developing something you’re passionate about, only to see slow initial growth or minimal user engagement.

There were definitely moments when I considered giving up. I was really disappointed by that Liftbear got such little traction, despite all the effort I put into it.

Turning a dream into a reality

The last 12 months feel like a dream to me.

From the leap of faith in leaving a secure job to the slow (then explosive) growth of my apps, the entire indie hacking process has been incredibly fulfilling.

I’m particularly proud to have built something that sustains my lifestyle and helps other people improve their own lives.

Christmas and New Year’s Eve is a very important season for habit-tracking apps and I was super proud to see HabitKit generate over $33,000 of revenue in a single month.

I have plans for a few new projects, but they’re all in their “secret” phase right now.

Start small and stay focused

As an indie hacker, your strength lies in simplicity. Try limiting your indie hacking business to solving a specific problem.

Focus on building a minimum viable product that addresses a real need, and then iterate based on user feedback. If it doesn’t resonate with users, move on and create something new.

I’d also advise against jumping on the latest trend. It might seem like a quick way to achieve success, but it can lead to a lack of focus and authenticity.

Focus on building something that genuinely interests you and serves a real need.

A marathon, not a sprint

When I first started as an indie hacker, I was super excited to see quick results. I underestimated how long it can take to build a successful product.

I wish I’d understood from the beginning that success often comes slowly and incrementally.

It’s important to be patient and persistent. Managing expectations is a really important skill for an indie hacker.

Building autonomy

One of the biggest achievements my indie hacking success has enabled is the transition to full-time self-employment.

Being my own boss and having the freedom to work on projects I’m passionate about has been incredibly rewarding.

It’s allowed me to create a lifestyle that makes me happy, where I have control over my time and the flexibility to work from anywhere. This autonomy has been one of the most fulfilling aspects of my indie hacking journey.

The main goal is being able to do this for a very long time.