iOS + Android in nine weeks. Zero criticals.

The problem

Coastline Health is a Series B telehealth startup with a working web application and a hard board deadline to ship native iOS and Android apps before their next funding round. Their existing web team had React expertise but no native mobile experience.

HIPAA compliance was non-negotiable. The app needed end-to-end encrypted messaging, video consultations, patient records access, and a full audit trail for every data access event — all wired into their existing EHR system.

They had evaluated React Native and decided against it: the video component and biometric auth requirements would have required native modules anyway. They wanted native Swift and Kotlin — and needed both platforms live in 9 weeks.

What we did

Week 1: architecture sprint. We mapped every API endpoint needed, defined the data model extensions for mobile audit trails, and selected LiveKit for video (self-hosted, HIPAA BAA available). We ran iOS and Android tracks in parallel with a shared Supabase backend.

The iOS app was built in SwiftUI with async/await throughout. Encrypted messaging used Signal Protocol via a custom Swift library. Biometric authentication (Face ID, Touch ID) used the Secure Enclave. Every API call and data access event wrote to an append-only audit log via a Supabase Edge Function — required for their HIPAA BAA.

The Android app mirrored the iOS feature set in Kotlin with Jetpack Compose. Material 3 design system, biometric auth via BiometricPrompt, and an offline-first architecture with WorkManager for background sync.

We ran a penetration test in week 7 and wrote integration tests for every HIPAA-critical path. App Store review was approved on first submission. Play Store review took 3 days.

Results

Both apps live in 9 weeks — iOS and Android simultaneously. Zero critical or high-severity bugs at launch, confirmed by their QA contractor's independent review. App Store rating reached 4.8★ in the first 6 weeks.

D7 retention hit 62% — significantly above the telehealth app industry median of ~44%. The founding team attributed this to the video consultation UX, which they said was noticeably faster and more reliable than the web app equivalent.

Tech stack

“Senior, fast, and refreshingly direct about what was salvageable. They told us what to keep and what to rewrite — and they were right both times.”