Hussien A.

"I can unreservedly recommend Hussein for the development and support of Android apps. Over the last 2 years, Hussein has delivered amazing work, providing everything we need for Android, Android Auto, and Android Automotive. I have been impressed with how quickly he has supported complex challenges including Mapbox integration, Android Automotive, cloud-based comms, SignalR, and MQTT. 100% recommended." - Client, UK Transport Authority I'm an Android engineer with 4+ years across product companies and freelance work. My specialty is apps that talk to hardware (BLE devices, car head units, sensors), but my day job is production Android at scale, so you get both. 🛠️ WHAT I'VE ACTUALLY SHIPPED 🛒 E-commerce (current role at a software studio): - Cut checkout loading from 12-15s to 2-4s (83% faster) by reworking GraphQL queries, caching, and business logic - Led full migration from XML to Jetpack Compose with MVI, reviewing code and supervising the team - Integrated Payfort and Paymob payment gateways, built Loyalty and Gift Card systems with animated Compose Canvas UI 🚗 Android Automotive & Auto (2 years, UK Transport Authority, UK): - In-vehicle warning app running on a Polestar head unit, tested at Warwick University, covered in industry press (LCRIG) - Road safety and city safety apps: Mapbox, Google Maps, real-time location, MQTT, SignalR - Trained a TensorFlow Lite model with CameraX detecting vehicles for driver safety scoring 📡 BLE & Embedded (my own product, end to end): - Designed a BLE wearable from zero: custom 4-layer PCB (nRF52840, PMIC, capacitive touch), Zephyr firmware with OTA firmware updates over BLE, a Compose Multiplatform (KMP) companion app, and a Ktor backend behind it. I debug every layer: sensor, firmware, app, and server. 🔒 Security & hardened apps: - Built a 7-layer protection system for a client app: Talsec RASP, custom C++ native module for Frida detection, hardware-backed AES-256 with Android Keystore, SQLCipher, ProGuard/R8, string encryption, certificate pinning - Secure chat app: message and file encryption, voice recording, CameraX capture, root detection, USB debugging prevention. Cut its CPU usage by 30% and memory by 80% through profiling - System-level call/SMS handling with CallScreeningService inside Android's 5-second response window ☁️ Backend & self-hosted: - Ktor REST APIs with MySQL, Exposed, and Docker, sharing a Kotlin module between server and app for type-safe contracts - Device telemetry (GPS with 5-tier fallback, signal strength, battery), OTA APK updates, FCM remote commands and Remote Config - I run my own self-hosted infrastructure (Docker, Linux, reverse proxies, monitoring), so I'm comfortable deploying and maintaining what I build 📱 MY OWN PRODUCT - GPA Manager on Google Play: 16K+ downloads across 80+ universities, live Firebase backend Plus 20 completed Upwork contracts: in-app purchases and subscriptions, survivable background services, GPS tracking, offline data capture, SDK migrations. 🤝 HOW I WORK GitHub access from day one so the code is yours at every step. Honest estimates before we start, clear updates while we work, and two weeks of free support after delivery. I usually reply within a few hours. If you're building something with a device, a car screen, or just need an Android app done properly, message me. The first consultation is free: tell me about your project and I'll give you my honest take on the approach, effort, and risks before you spend anything.