Leg Day
Meet people at your gym.
Social
UI/UX
Frontend
Role
Founding Engineer
Timeline
10 weeks
team
Me + 1 Engineer
platform
iOS, Web
What is Leg Day?
Leg Day is a social app meant to connect people at the gym. As a Founding Engineer, I was responsible for the frontend development and branding for this application — shaping how every member experiences the product from the moment they hear about us to the moment they meet someone in real life.
My contribution
On the mobile side, I designed and built the entire new-member onboarding flow in React Native (Expo), including an interactive tutorial that teaches users how mutual matching works before they ever swipe on a real profile. A central proponent to this app is a hands-on Discovery → Rolodex demo: a guided sequence of animated profile cards that the user shakes, swipes, and "matches" with, all driven by gesture and Reanimated 3 transitions. Beyond onboarding, I created a profile editor, the gym check-in experience, the gesture-driven card stack, the visibility controls that let members decide who can see them, and other small details including phone authentication, photo upload, range sliders, etc.
Explanation Flow
I also designed and shipped legday.nyc, the company's public marketing site, end-to-end in Next.js. The page opens with an animated mesh-gradient hero and a scroll-driven sequence of story sections that mirror the app's actual interactions — an auto-toggling visibility switch, a Rolodex-style mutual-match animation, scrollytelling around location and serendipity — and closes with a waitlist form that captures Instagram and TikTok referrals so the team knows where signups are coming from. The goal was to make the website feel like a continuation of the app, not a separate marketing artifact.
As one of two engineers, I shipped ~100+ changes across the app and site, helping take Leg Day from prototype to a live iOS app with real members checking in at real gyms. The work spanned visual identity, motion design, frontend architecture, and the minor details that connect them.
What I learned + takeaways
This was my first time developing a mobile app using React Native, and there were many hurdles along the way to completion. It was challenging to complete certain components of the application given the time constraints, and so building a functional app from scratch within 4 months was a much more daunting task than I initially perceived.
Ultimately, I took away many lessons from this experience. What made this project exceptional wasn't the tech stack. It was the gap between what I knew when I started and what the company needed from me on a weekly basis. I'd done frontend work before, but never React Native, never iOS-specific patterns, never a real-time social product where every screen had to feel native and a half-second of jank could kill the vibe. I learned the framework by shipping in it, such as gesture handlers, navigation stacks, and push notifications, usually about a week ahead of when each piece was due. The design side ran in parallel: I was prototyping flows in Figma, getting feedback from the founders, then implementing them myself, which meant I couldn't hide behind "the designer specced it this way." If it felt wrong on the phone, that was on me to fix.
The part I'm proudest of is harder to point at in a screenshot. It's that the app shipped, real users opened it, and the interaction patterns I made up under time pressure mostly held up. A few of them didn't, and I learned more from rewriting those than from anything that worked first try.
Leg Day is currently available on the App Store, and was recently featured in a New York Times article.
