Case Study · Q2 2025 -> Q4 2025 (7 months)
From clunky prototype to 27% day-30 retention — on iOS and Android, from one codebase
27%
Day-30 retention
8% → 27%
4.7
App store rating
3.2 → 4.7
99.6%
Crash-free sessions
91% → 99.6%
6.8 min
Avg. session length
2.4 min → 6.8 min
Industry
Technology — Mobile App
Stage
Seed startup, 12 employees
Geography
Global
Service
Hybrid Mobile App Development
The Challenge
Burning runway. One platform. No retention.
A fitness startup needed to ship on both iOS and Android fast — without the cost of two native teams. Their early prototype was clunky, day-30 retention sat at 8%, and the app store rating made organic discovery hard. Runway was burning before they reached a sustainable user base.
Day-30 retention8%
App store rating3.2 stars
Crash-free sessions91%
Avg. session length2.4 min
“An early native iOS prototype that was slow to iterate and too costly to also build for Android.”
Before vs. After
From a clunky single-platform prototype to a polished cross-platform app that actually retains users.
Before
After
What We Did
Ship one codebase. Earn the first win. Loop the user back in.
Channels
- Cross-platform app development
- UX/UI redesign
- Onboarding + retention optimization
Tools
- React Native / Expo
- Figma (UX/UI)
- Firebase (auth, analytics, push)
- App Store Connect + Google Play
Key Tactics
- 01Rebuilt the app on one React Native + Expo codebase so iOS and Android ship together — cutting development cost and matching feature parity on every release
- 02Redesigned onboarding to deliver a first measurable 'win' in under two minutes — the lever that determines whether a fitness user comes back on day 2
- 03Added push-notification habit loops, streaks, and reminders tuned to each user's behavior to drive day-30 retention without spamming
- 04Stabilized performance and instrumentation — pushed crash-free sessions to 99.6%, which directly lifts store ratings and organic install rate
The Results
Every metric moved. Verified in Firebase + App Store Connect.
Day-30 retention
8%
→
27%
+238%
App store rating
3.2 stars
→
4.7 stars
+47%
Crash-free sessions
91%
→
99.6%
+9%
Avg. session length
2.4 min
→
6.8 min
+183%
Beyond the Numbers
- Shipped to both platforms from a single codebase, extending runway
- Higher ratings improved organic app-store discovery and install conversion
- Retention gains strengthened the metrics deck for the next funding round
“
They got us on both app stores from one codebase and actually moved retention. That's the number our investors care about.
— CEO, Health & Fitness App Startup (anonymized)
Launching an app? Ship to both stores without the dual-team cost.
Book a free 30-minute strategy call. We'll look at your feature scope, your retention model, and your timeline — and tell you honestly whether a hybrid React Native build fits or whether native is the right call.