You have ten or more years of mobile engineering experience and you have built mobile applications from the ground up — not joined them, not iterated on them, but defined the foundation and shipped it to production at scale. You have an honest, scarred view of what mobile platform decisions cost three years after you make them.
You are deeply expert in at least one of iOS or Android, and seriously fluent in the other. On iOS that means Swift, the Swift concurrency model, UIKit and SwiftUI, the Apple toolchain and release process, and the parts of the ecosystem most engineers learn the hard way. On Android that means Kotlin, coroutines and Flow, the Android lifecycle, Jetpack and Compose, Gradle in earnest, RxJava where it still lives, and the same hard-won understanding of the ecosystem.
You understand the cross-platform landscape with the same honesty. You have an opinion on Flutter, KMP, and React Native that goes beyond preference — performance characteristics, ceiling, where each shines, where each fails — and you can defend the recommendation you would make for a fintech app at Payoneer’s scale.
You have built and operated a modular mobile platform before, or something close enough that you understand the trade-offs: how to define module boundaries that survive ten product teams contributing in parallel, how to keep the host app coherent when contributors disagree, how to version a contribution model without breaking everyone, and how to keep the binary lean as the surface grows.
You think in budgets and measurements. You have driven startup time, frame rate, binary size, and crash-free rate as numbers on a dashboard. You understand mobile observability at a level beyond crash reporting, and you have shipped the instrumentation needed to debug productio.
You communicate clearly with engineers, product partners, and executives. You can write a one-page architecture proposal, run an RFC that actually converges, demo what you built so other engineers want to use it, and explain a stack decision to a CPO in language they care about. You handle disagreement well — including with your peer Principal — and you know how to land a joint decision.