👋 Mina Mikhail

📱 Principal Android Engineer | 🏦 FinTech & Digital Banking | 💳 POS Systems

8+ years building production-grade Android applications

Android engineer based in Cairo, Egypt with deep expertise in fintech, digital banking, and payment systems.

I build apps that handle real money for real users in real markets.

My work spans POS terminals, secure transactions, modular architecture, and high-availability applications deployed across Egypt, Pakistan, and Saudi Arabia.

I spend 2 hours daily learning new technologies. Android is a long-term craft, not a trend.

What I care about:

• Clean architecture that scales
• Testable code that catches bugs before users do
• Performance under real constraints
• Systems that fail safely

Principal Android Engineer

Building Egypt's first digital bank.

• Modular Android architecture for enterprise-scale apps
• Authentication systems with multiple strategies (OTP, Biometric, DFI)
• FATCA/KYC compliance implementations
• Token and session management systems
• CI/CD with quality gates

Senior Android Engineer – FinTech & POS

• Developed Android apps for POS payment terminals
• Worked on card transactions, EMV, and secure payment flows
• Deployed apps used across Egypt, Pakistan, and Saudi Arabia
• Focused on stability, latency, and offline handling

Category	Technologies
Languages
Architecture	Clean Architecture, MVVM, MVI (Orbit), Modularization by Feature
Async	Coroutines, Flow, StateFlow
DI
Networking	Retrofit, OkHttp, Ktor
Database	Room, DataStore
UI	Jetpack Compose, DataBinding, Navigation Component, Material Design
Testing	JUnit 4/5, MockK, Mockito, Kover, Orbit Test
CI/CD	GitHub Actions, Jenkins, SonarQube
Build	Gradle KTS, buildSrc
Tools

Production-ready Android template with clean architecture and modern tech stack.

Features:

• Clean Architecture with Domain, Data, Presentation layers
• Navigation Component with multiple backstack support
• Hilt dependency injection
• Kotlin Coroutines and Flow with StateFlow
• Git hooks for code quality automation

Tech Stack: Kotlin, MVVM, Hilt, Coroutines, Flow, StateFlow, Retrofit, Navigation Component, DataBinding

Modules: app, domain, data, presentation, appTutorial, actionChooser, prettyPopUp, imagesSlider

Secure biometric authentication with Cipher encryption/decryption for sensitive data.

Features:

• Biometric login with fingerprint/face authentication
• AES encryption/decryption using Android Keystore
• Secure storage of user credentials
• Clean modular architecture

Tech Stack: Kotlin, Biometric API, Android Keystore, Cipher, Hilt, Encrypted SharedPreferences

Modules:

• biometricAuthentication — Handles biometric prompt and authentication flow
• crypto — Manages encryption and decryption operations
• prefs — Encrypted SharedPreferences wrapper

Screens: Splash (biometric login), Login (credential encryption), Home (user data display)

📚 Biometric Authentication Presentation

Test data generation library for Android unit testing.

Features:

• Generate dummy values for any data class
• Support for lists with configurable size
• Easy customization with .copy() for specific test scenarios
• Reduces boilerplate in unit tests

Usage:

// Generate single object
val user = fixture<User>()

// Generate list with specific size
val users = fixtureList<User>(10)

// Override specific fields
val customUser = fixture<User>().copy(name = "Test User")

Why use it:

• Eliminates hardcoded test data
• Makes tests more readable
• Catches business logic changes when combined with exact mocking

Retrofit adapters for handling API responses and exceptions in clean architecture.

Features:

• Custom Retrofit Call Adapter for unified error handling
• Sealed class response wrapper for success/error states
• Network exception handling without try-catch blocks
• Clean separation between network and domain layers

Tech Stack: Kotlin, Retrofit, OkHttp, Clean Architecture

Use Case: Centralized API error handling that propagates errors through the architecture without exposing Retrofit exceptions to the domain layer.

Sample news application demonstrating modern Android development practices.

Features:

• Fetch and display news articles from API
• Local caching with Room for offline support
• Image loading with Coil
• Clean MVVM architecture

Tech Stack: Kotlin, Hilt, Coroutines, Coil, Room, Retrofit, MVVM

Architecture: Repository pattern with local database as single source of truth. API data is cached locally and served from Room database.

Cache-first strategy for API response caching to local storage.

Features:

• Cache-first data loading strategy
• Automatic cache invalidation
• Offline-first architecture
• Seamless online/offline transitions

Use Case: Apps that need to work reliably with intermittent network connectivity while keeping data fresh.

This GitHub contains:

• Android architecture experiments
• Clean code samples
• FinTech-oriented patterns
• Real solutions to real problems

Code here reflects production thinking, not tutorials.

✅ Single Responsibility — Each class has one job
✅ Testability First — Write code that can be tested in isolation
✅ Performance Matters — Optimize for real constraints
✅ Fail Safely — Systems should degrade gracefully
✅ Simplicity Scales — Better than cleverness
✅ FinTech Code Must Be Boring and Correct