I need a production-ready Android application built from the ground up. The core requirements are clear: secure user authentication, smooth in-app purchases, and reliable push notifications. I’m looking for a developer who can take the project from initial architecture through release on Google Play, ensuring the codebase is fast, modular, and easy to scale. Here is what matters most to me: • Authentication must be rock-solid, ideally using modern approaches such as JWT or Firebase Auth while respecting Google’s latest security guidelines. • In-app purchasing flows should feel native and frictionless, with clear validation on both client and server sides. • Push notifications have to be timely and configurable, using FCM with options for segmented or broadcast messaging. I already have basic wireframes and a feature list; you’ll refine the UI into a clean Material-compliant design, hook everything to a well-structured backend (REST or GraphQL—your call), optimise performance, and hand over installable APKs plus all source code in a private repo. Acceptance criteria 1. Login, sign-up, and password-reset journeys verified on real devices. 2. Successful test purchase processed in Google Play Console’s closed track. 3. Push notification received and opened from app background, foreground, and terminated states. 4. Code passes linting, unit tests cover critical logic, and README explains setup. If you’ve shipped Android apps with these exact features before, tell me briefly about your stack choice and estimated timeline, and let’s get started.