End-to-End E-Commerce Android App

I need a skilled Android developer to turn my e-commerce concept into a polished, production-ready application. The app must feel fast and intuitive on any recent Android device and follow a clean, custom design language that we’ll refine together during development.

Core scope
• Build the entire Android application in Java or Kotlin inside Android Studio, using XML layouts (or Jetpack Compose if you strongly prefer and can justify the gain).
• Implement the three must-have modules:
– Secure user authentication with personal accounts (email, Google, or phone-based sign-in via Firebase Auth or a comparable solution).
– Robust product catalogue with search, category filtering, and real-time stock/price data pulled from a REST API or Firebase/Firestore.
– Smooth shopping cart flow culminating in a checkout screen ready to plug into a payment gateway (Stripe, Razorpay, etc.—I’ll supply the keys).
• Handle all back-end conversations through clean REST calls or Firebase, persisting essentials locally for offline grace.
• Follow responsive design principles so screens adapt neatly from small phones to large tablets while keeping the bespoke visual style we define.
• Test on multiple API levels, fix any crashes or layout breaks, and deliver a release-ready APK plus the complete, well-commented source code.

Please include in your proposal:
1. A short portfolio of Android apps you have published (links or APKs).
2. Your estimated timeline broken into key milestones (design hand-off, alpha, beta, final).
3. A rough cost range for the full build, including at least one post-launch bug-fix cycle.

I’m ready to supply wireframes, brand assets, and API documentation as soon as we agree on scope. Let’s create an e-commerce experience that stands out for its speed, clarity, and professional finish.