Sergey L.

I am a Software Developer with 25+ years of professional experience, starting my career in 2000. Throughout my career, I have designed, developed, maintained, and improved a wide range of software solutions, from mobile and desktop applications to complex client-server systems and hardware integrations. My primary specialization is Android development using Kotlin and Java, including modern Android development with Jetpack Compose. I also have experience with cross-platform mobile development using Flutter and Dart, as well as Windows desktop application development using C# and C++. Throughout my career, I have worked on projects of different scales and complexity, gaining extensive experience in software architecture, application development, third-party integrations, networking, multimedia technologies, and hardware communication. ======================================== MOBILE APPLICATION DEVELOPMENT ======================================== - Native Android development using Kotlin and Java - Modern Android UI development with Jetpack Compose - Cross-platform development using Flutter and Dart - iOS development experience with Swift and Objective-C - Application architecture, maintenance, debugging, and performance optimization - Integration with REST APIs and third-party services ======================================== FIREBASE & BACKEND INTEGRATION ======================================== Hands-on experience integrating mobile applications with backend services and Firebase: - Firebase Cloud Messaging (FCM) - Firebase Crashlytics - Firebase Analytics - Firebase Remote Config - Firebase Authentication - REST APIs, HTTP/HTTPS, JSON - Client-server communication and authentication - Real-time data exchange ======================================== IN-APP PURCHASES & SUBSCRIPTIONS ======================================== Experience implementing and maintaining monetization systems for mobile applications: - Google Play Billing - RevenueCat - Adapty - In-app purchases and subscription management - Purchase validation - Subscription lifecycle integration ======================================== PRODUCT ANALYTICS ======================================== Experience implementing analytics and tracking user behavior to understand application usage, engagement, and conversion: - Amplitude - Firebase Analytics - Custom event tracking - User behavior and engagement tracking - Conversion tracking ======================================== WINDOWS & DESKTOP DEVELOPMENT ======================================== Experience developing Windows desktop applications and integrating software with external hardware: - C# and C++ - Delphi - Windows application development - Hardware and device integration - Multimedia technologies and video processing ======================================== NETWORKING & HARDWARE INTEGRATION ======================================== Extensive experience working with networking, communication protocols, and video surveillance systems: - TCP/IP, UDP, SIP, VoIP, WebRTC - DirectShow - DVR/NVR systems and boards - CCTV and IP cameras - Hikvision and Dahua devices - I/O devices and hardware interfaces ======================================== ADDITIONAL TECHNOLOGIES ======================================== - Programming Languages: Kotlin, Java, Dart, Swift, Objective-C, C++, C#, Delphi - Databases: SQL, MySQL, SQLite - Web Technologies: PHP, JavaScript, jQuery, AJAX, HTML, CSS, Vue.js, TypeScript, Ionic - Cloud & Infrastructure: AWS, Zoho, Apache ======================================== APPLICATION PUBLISHING & MAINTENANCE ======================================== Experience managing the Android application release lifecycle: - Publishing applications through Google Play Console - Preparing and delivering application updates - Version management and release configuration - Managing production releases - Maintaining and supporting existing applications ======================================== HOW I WORK ======================================== I have extensive experience working both independently and as part of development teams, collaborating with developers, designers, QA engineers, and other stakeholders. I am comfortable taking ownership of technical tasks, contributing to architectural decisions, analyzing existing codebases, reviewing and improving code, and working with both new and legacy systems. I value clear communication, knowledge sharing, and a collaborative approach to solving technical challenges. My focus is on writing reliable, maintainable software and delivering practical solutions that meet project requirements and business goals. Whether you need to develop a new Android application, improve an existing product, integrate third-party services, implement subscription systems, or maintain a complex software solution, I can bring extensive development experience to your project.