Can you introduce yourself and share a bit about what you were doing before Livity?
I started my developer career at SEB, then moved to Vinted as an iOS developer - spent about two years there, which was a great experience working on a product used by millions. After that, I was freelancing, with Qonto being my main client - a French fintech focused on SMEs. That period of freelancing actually gave me the time and space to start building Livity, which eventually turned into my full-time focus.
What is Livity and what problem does it solve? Why did you decide to build this specific product?
Livity is a privacy-first health and fitness tracking app for iPhone and Apple Watch. Think Whoop or Oura - but without the hardware. It tracks your recovery, sleep, strain, stress and heart rate zones using data you already have. I built it because I play volleyball and wanted to track my training and recovery properly. Everything out there either costs too much or requires buying another device. So I just built what I needed myself - and now more than 40,000 people use it.
What does a typical day look like for you as a founder?
Volleyball at 7:30, then breakfast, then I'm at my desk. I go through all the support emails first, check feedback, then it depends. If I'm deep in a new feature - I'm building. If something just shipped and I'm in maintenance mode - I switch to marketing, ads, distribution. It shifts constantly. I just follow where the product needs me that day.
What has been your biggest challenge so far?
Marketing. 100%. Building is the fun part. Making people actually see the app - that's the hard part. Trying different strategies, doing media buying, figuring out what works, all while still being the developer, the support guy, and the founder. It's a lot of hats.
How do you currently collect and manage feedback from your users?
Reddit is my main one - r/livityApp, over 1,200 members. They're the first to know about new features and honestly the first to find the bugs too. Because of them, I can fix things fast and actually understand how people use the app. I also have a feature voting board where users suggest and vote on what they want. Makes prioritization pretty easy.
How do you decide what features to build next and put on your roadmap?
The voting board tells me. Users add what they want, vote on it, I can see what wins. No guessing. The people using the app every day tell me what to build next.
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What are the top 3 tools or apps your team uses every day?
Claude Code for building, Figma for design, Reddit for everything community-related.
How do you use AI in your daily work or inside your product?
When I'm building a new feature I use it to research first, not just code. I'm currently building a Heart Rate Reserve feature - Claude gave me a two-page breakdown of the science and a full building plan before I wrote a single line. That's the kind of thing that used to take days.
Inside the app we have two layers of AI. The first runs fully on-device using Apple's foundation models - short daily overview of your sleep, recovery, strain, nothing leaves your phone. The second is an optional AI chat where you can dig into your health data and ask questions - but users have to explicitly opt in.
What has been your biggest mistake or learning so far?
How I handled the switch to paid. I launched free to collect feedback - right call. But when I monetized, even though I gave early users continued access, they felt blindsided. Got a wave of bad reviews. The lesson wasn't "don't launch free" - it's that you have to bring people along with you when things change. Communication is everything.
What is one piece of advice you would give to someone starting a startup today?
Build something you actually use. Launch it free, get real feedback, build a community - then charge. Just make sure when you do make that switch, you bring your early users with you. How you communicate it matters as much as the decision itself.
What is the next big goal for Livity?
More devices - Garmin is already in progress. Better AI features. And eventually combining health data with AI through MCP, which I think is going to make personalized health coaching actually good.
Good luck!
Thank you to Martynas for sharing his time and insights with us. You can learn more about Livity and download the app at livity-app.com.
