Mobile Engineer Android (Kotlin) for crypto trading terminal

Must-have

• 4+ years shipping native Android apps in Kotlin, with at least one public Play Store app they can name and describe their ownership of.

• Shipped a realtime, high-message-rate app (trading, live odds, ride-hailing, auctions, telemetry). Specifically: persistent socket connections, backpressure, reconnect/resubscribe logic, and UI updating many times per second without dropping frames.

• Bidirectional protocol experience (Socket.io, raw WebSocket, MQTT, gRPC streaming, SSE). Socket.io is a plus. The Java/Kotlin client is rougher than the JS one, and the candidate should know that.

• Secure on-device credential handling: Keystore/StrongBox, BiometricPrompt, EncryptedSharedPreferences.

• Correctness-critical domain experience: fintech, banking, brokerage, payments, crypto, healthcare etc.

• Owns the release pipeline (signing keys, app bundles, CI builds, staged rollout, crash reporting) and has personally handled a Play Store rejection and gotten the app approved.

Android specifics

• Kotlin depth: coroutines, Flow (StateFlow/SharedFlow, conflation, buffering for a firehose), structured concurrency.

• Architecture: ViewModel, Navigation, WorkManager, Room/SQLDelight. DI with Hilt or Koin.

• Networking: Retrofit/OkHttp; Socket.io Java client or OkHttp WebSocket.

• Java interop for third-party SDKs. Java-only with no production Kotlin is not a fit.

• Play Console: signing keys, app bundles, staged rollout, pre-launch reports, Financial Services and crypto-exchange declarations.

• Platform constraints: background execution limits, Doze, foreground-service policy (for price alerts), device fragmentation, low-end device performance, R8/ProGuard.