Jeffy Lazar

Led end-to-end delivery of FanCenter features in ESPN BET sportsbook app, delivering a personalized betting experience by connecting user fandom and fantasy rosters to tailored markets. Built a server-driven UI system that renders dynamic components, improving engagement with game-specific content. Owned feature delivery from planning to release, collaborating across backend, product, QA, and design. Modernized architecture by introducing modular, Compose-based surfaces, improving portability and build stability. Implemented comprehensive unit tests (JUnit, Mockito) achieving high coverage. Leveraged Kotlin Coroutines Flow for efficient data fetching and state management. Used GraphQL (Apollo Client) with subscriptions to enable real-time data. Added Datadog analytics to track user journeys and product decisions. Diagnosed crash trends with Firebase, reducing runtime issues. Refactored legacy XML components to modular Compose surfaces to reduce regressions and speed up development.

Led end-to-end Android development for multiple enterprise applications across maintenance, reporting, and inventory domains. Defined requirements, architecture, implementation, and release cycles. Built a Bluetooth/USB serial communication tool enabling technicians to read/write elevator controller parameters, improving operational efficiency. Implemented robust multithreading for real-time synchronization with microcontrollers and created a high-performance, real-time oscilloscope visualization using MPAndroidChart, reducing diagnostic time. Added offline-first data pipelines with SQLite/Room and multi-threaded sync with conflict resolution. Integrated Google Maps routing, Play Billing, FCM push notifications, barcode/QR scanning, and PDF generation. Implemented server-driven UI rendering and multi-fragment tablet layouts for multi-client customization. Collaborated with Backend, iOS, QA, and clients across regions, and utilized Android Profiler for performance tuning.

Designed complex login flows for varied user types and integrated with payment gateways. Implemented mobile number verification and managed full lifecycle of the application, including testing, debugging, and deployment. Migrated the app to Material Design concepts and implemented a Download Manager for Tender documents.