FIRAT CEM TOPAL
Building scalable mobile architectures & payment systems. 7+ years crafting high-traffic Android apps while surviving off coffee and sheer panic. I make your phone go beep boop without crashing. Mostly.
SENIOR ANDROID ENGINEER (PROFESSIONAL BUG CREATOR)
Senior Android Engineer with 7+ years of experience specializing in scalable mobile architectures, payment system integrations, and in-app subscription models (Google Play Billing). Passionate about building developer-centric tools and SDKs. Skilled in Kotlin, Jetpack Compose, Java and CI/CD pipelines, with hands-on experience in cross-platform development (Flutter). Proven track record of optimizing monetization flows for high-traffic applications like Muud and Obilet.
WHERE I'VE MADE IMPACT
Turk Telekom A.Ş.
Expert Android Developer
- Architected and maintained the In-App Subscription module using Google Play Billing Library, directly contributing to the app's monetization strategy and revenue growth. Focused on handling complex subscription states and grace periods.
- Enhanced user satisfaction by 20% through improvements in playlist management and offline music functions.
- Integrated Material 3 design principles into the Muud App, enhancing UI consistency and user experience.
- Designed reusable UI components using Jetpack Compose, serving as an internal library for the team to ensure consistency and speed up feature development.
- Developed and executed a comprehensive suite of integration tests that reduced backend connectivity issues by 50%, leading to more reliable feature delivery and improved user satisfaction across the Muud App's functionality ensuring high product quality and reliability.
- Integrated and managed third-party SDKs for user acquisition campaigns, ensuring seamless functionality and data flow within the main application.
obilet.com
Android Developer
- Developed B2B and B2C Android applications, achieving 10M+ downloads and a 4.8/5 user rating on the Google Play Store.
- Redesigned architecture using Jetpack Libs and implementing MVVM pattern, improving dependency management and code maintainability.
- Developed comprehensive test suites using JUnit, Mockito, and Espresso, achieving 95% code coverage.
- Conducted peer code reviews to uphold best practices in clean architecture and Material Design principles.
- Led the engineering of a secure, multi-provider payment module integrating Masterpass SDK and Bank POS systems. Abstracted payment logic to support scalable integration for various B2B/B2C partners.
Kentkart
Mobile Application Developer
- End-to-end carded/cardless payment systems for public transportation have been developed using NFC technology on Android devices.
- Built secure NFC-based payment SDK/module for public transportation, utilized by thousands of users daily. Improved transaction reliability by 30% through low-level optimization.
- Optimized app performance using profiling tools, reducing transaction processing times by 25%.
- Delivered seamless user experience through integration of modern Android platform features.
Itech Otomasyon Ar-Ge Merkezi
Ar-Ge Employee
- Developed IoT Beacon Asset Tracking solutions, enabling real-time customer traffic tracking and heatmaps for retail.
- Built AGV vehicle tracking and routing Android applications, utilizing Google Maps API, MQTT, and WebSockets for precision routing.
TECHNOLOGIES & EXPERTISE
LANGUAGES
FRAMEWORKS & TOOLS
TECHNOLOGIES
SOFT SKILLS
ARCHITECTURE
TESTING
CI/CD & TOOLS
APPS I'VE BUILT & SHIPPED
HIGH-TRAFFIC APPLICATIONS WITH MILLIONS OF DOWNLOADS AND 4.8+ RATINGS
MUUD MÜZIK
With Muud, the most popular songs, the latest albums, news, events, and ready-made playlists based on genres and trends are refreshed on your homepage every minute. You can easily follow everything you're looking for about music here.
OBILET: OTEL UÇAK OTOBÜS ARAÇ
Obilet is a travel application that offers advantageous opportunities where you can purchase plane, bus, and ferry tickets from among many options, rent a vehicle from your preferred company, and book a reservation at your desired hotel to reach your dream vacation with a single click.
LET'S BUILD SOMETHING WEIRD AND GREAT
ALWAYS OPEN TO DISCUSSING NEW PROJECTS, OPPORTUNITIES, OR JUST ARGUING ABOUT TABS VS SPACES.
LET'S CONNECT
WHETHER YOU HAVE A PROJECT IN MIND, WANT TO COLLABORATE, OR JUST WANT TO SAY HI — I'D LOVE TO HEAR FROM YOU.
BEST FOR PROJECT INQUIRIES
CHECK OUT MY CODE
PROFESSIONAL NETWORK