Senior Android Mobile App Developer — Kotlin, AI/LLMs, OS Integration (plus Flutter / React Native)

Overview Looking for an experienced senior mobile developer to join a short-to-medium term project building and evolving a mobile app with strong Android/Kotlin foundations and deep experience integrating AI/LLM APIs. The role requires hands‑on implementation, architecture guidance for AI features (on-device and cloud), and the ability to build/extend cross‑platform modules (Flutter / React Native / Kotlin Multiplatform). This is not a pure UI-only role — we need someone who can design secure LLM integrations, implement OS-level features, optimize performance, and mentor other engineers. What you’ll do - Lead development of Android app features in Kotlin (architecture, implementation, testing, releases). - Design and implement integrations with LLM APIs and AI services (OpenAI, Anthropic, Azure OpenAI, etc.) including streaming, prompt engineering, rate‑limiting, retry and cost control. - Work on AI/ML on-device and hybrid approaches (embedding models, on-device LLMs or client-side inference where appropriate). - Implement secure handling of API keys, token refresh, and privacy-preserving data flows. - Build OS integrations: background tasks, notifications, sensors, intents, deep links, file & media access, platform permissions and battery/network considerations. - Create native modules / bridges for Flutter and React Native when required; design Kotlin - Multiplatform (KMP) modules for shared business logic. - Improve app architecture for reliability and observability (logging, metrics, crash reporting). - Write unit & instrumentation tests, set up CI/CD pipelines and support releases to Play Store / App Store (as needed) Must‑have (required) - 5+ years native Android development with Kotlin (strong, idiomatic Kotlin). - Practical experience integrating LLM APIs and AI services (examples of shipped features). - Strong understanding of mobile security best practices for API keys, user data and network flows. - Experience with OS integration: background processing, notifications, intents, storage, permissions. - Experience building native bridges or modules for Flutter or React Native OR strong KMP experience (Kotlin Multiplatform). - Solid software engineering practices: automated tests, clean architecture, dependency injection, modularization. - Clear written and verbal English communication and ability to explain technical tradeoffs. Deliverables (examples) - Production‑ready Android Kotlin code for LLM integration (including secure API handling). - Cross‑platform/native bridge or KMP module for shared logic. - Tests (unit / UI where applicable) and CI pipeline to run them. - Short architecture document describing AI integration approach, security, cost control and offline strategy. - Knowledge transfer and code review notes. How to apply Include the following in your proposal: - Short cover message (1–2 paragraphs) explaining why you’re a fit. - Your hourly rate or fixed bid for initial milestone + estimated weekly availability. - Links to 2–3 relevant portfolio examples or repositories (prefer examples showing LLM/AI mobile work or cross‑platform native modules).