Building Frenby, a Compose Multiplatform Social App for Finding Friends Nearby

I have been living in Germany for the past 9 years. I moved here to do my master's in media informatics at the University of Bremen. Germany is a country where, when you ask people to meet, they give you an appointment for next week or, in most cases, an appointment in two weeks. In the cold, dark winter, that feeling that no one is available for you instantly makes you feel sad and lonely. I am sure this problem not only exists in Germany but all over the world. We are living in a post-pandemic AI era where your social interactions with other humans are becoming minimal. Imagine your social battery is at 10%; you want to meet someone to talk or do some activity together, but no one is available. I am sure we all have been through that at least once in our lives. Not everyone is comfortable joining big events to interact with people; sometimes you just need one or two to do something together. That’s when the idea of Frenby clicked in. In my vocabulary, Frenby is a short form of “Friends Nearby“. So, how is Frenby solving this problem? How sad can it be? Two people nearby, both are lonely but don't know how to meet.What is Frenby? Frenby (frenby.com) is an app available on the Apple App Store, Google Play Store, and Samsung Galaxy Store that helps you to meet people nearby who are up for the same thing as you. Now, at this moment, today, or at most tomorrow, not in one or two weeks. Sounds cool, right? How did I build Frenby? Before starting to work on it, three things were clear in my mind: I am going to work on it alone, I want to make it live on two platforms, and I have no funding or money to spend on this project. I am an engineering manager by day with 11+ years of experience in mobile and customer-facing app development, so I know how much a two-platform mobile app costs in people. I did not have those people. I just had my evenings after work. So the first commit in February 2026 was a Kotlin Multiplatform project. Shared business logic, shared data layer, and even shared UI through Compose Multiplatform. As a fan of Jetpack Compose for Android, I've always wanted to try Compose Multiplatform; my curiosity about how it would work on iOS, plus my prior knowledge, led me to choose it over other multiplatform options. I couldn’t find any social app using Compose Multiplatform, so the only way for me to know whether it would work or not is by doing it. And I am happy to say that it did work for me. Compose Multiplatform enabled me to have one codebase for Android and iOS, and platform-specific code was written only where the operating system forces it, such as location permissions, the photo picker, push notifications, and the QR scanner. This is the decision I would make again without any hesitation. Roughly 70 commits later, the vast majority of Frenby’s features were served by one codebase and worked on both platforms. The only places where KMP made me work twice were the places that one would predict. Anything that touches your native permission dialog Anything that touches a native Google Play Console or Apple App Store’s own SDKs Anything where you have to use your phone’s hardware, such as the camera, etc. The second constraint for me was money. Frenby is bootstrapped; I didn’t take any funding. So there was no choice like we will optimize the cost later. Every feature had to be designed around what it costs to run at zero users and at multiple thousands. A few things to keep in mind when working on a bootstrapped project, Read cost is a design decision, not an optimization, so keep it low from the beginning Window any historical lists in your project instead of paginating it; for example, we did it with previous chat messages Debounce anything that fans out; it might look like a single small write, but it will cost a read to every subscriber listening to it Upcoming challenge: I am going to integrate RevenueCat for Plus and Max subscriptions in the Frenby app. I might create a separate article for that. How does Frenby work? Very simple, Just share what you’re up for? Coffee, Chai, Beer, Ping Pong, Gym, Gossip, Run, Board Games, Hangout, Food, Picnic, Party, Walk, etc. See Nearby frens in a grid; check who is up for what? See your neighborhood Pulse: who is up for what, who Frenbified with each other? Wait… what is Frenbify? Chat with frenbies by texting them or sending a voice note. But please, no dirty talk; you have tons of dating apps out there to do that. 😀 You can also share your location, which will expire in an hour. But stay safe; don’t share your location if you don’t get a good vibe from the person. So coming back, what is Frenbify? When you meet someone, you can vouch for each other by scanning the expiring QR codes in the app. And then it will be posted in Pulse and also shown in your profile. You get a Frenbified badge once two people have vouched for you. You have all the controls. Decide whether you want to be visible to men, women, non-binary, or everyone. The choice is yours. But your chances to meet a frenby are stronger if you stay open to everyone. Add your interests, languages you speak, and neighbourhood to your profile. Collect the First Frenby badge if you are the first one in your neighbourhood to share what you are up for. Upgrade to Plus or Max to see more Frenbies or use the app in Incognito Mode. How does Frenby works?Is Frenby live? Frenby is almost live; please check frenby.com and join our waiting list. Frenby app is currently in Closed Testing on the Google Play Store. Under development for the Apple App Store and Samsung Galaxy Store. We will be live in September 2026, as we are participating in RevenueCat’s #Shipaton. Let’s win it! Follow Frenby on Instagram, Reddit, and X.