Practical lessons from 12+ years of building and shipping mobile apps.
End-to-end encryption is easy to describe and brutal to operate on real phones, where keys live in the Keychain and Keystore and survive, or vanish, in ways that surprise you.
Getting WebRTC calls to actually connect was the easy part; keeping them alive through CallKit, audio sessions, and a leaked camera light was the real work.
Syncing Apple HealthKit data into a clinical backend sounds simple until duplicates, wrong timezones, and vanishing deletions teach you that clinical data has to be exactly right.
After a few back-to-back video consultations the iOS app's memory kept climbing until the OS killed it, so I went retain-cycle hunting.
Practical experience migrating a live streaming project from Objective-C to Swift, valuable lessons and best practices.