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Hi, I’m Jeffy Lazar, a Senior Android Developer based in Kitchener, Canada. I excel at building mission-critical mobile experiences, modernizing legacy apps, and delivering end-to-end features with a strong focus on performance and reliability. I’ve spent 9+ years crafting scalable Android architectures, mentoring teammates, and collaborating with product, design, and backend teams to ship high-quality software.\n\nI’m passionate about turning complex requirements into modular, testable code. I enjoy applying MVVM, Clean Architecture, and Jetpack Compose within multi-module architectures to create maintainable, fast, and user-focused apps that scale with user demand and business needs.…Hi, I’m Jeffy Lazar, a Senior Android Developer based in Kitchener, Canada. I excel at building mission-critical mobile experiences, modernizing legacy apps, and delivering end-to-end features with a strong focus on performance and reliability. I’ve spent 9+ years crafting scalable Android architectures, mentoring teammates, and collaborating with product, design, and backend teams to ship high-quality software.\n\nI’m passionate about turning complex requirements into modular, testable code. I enjoy applying MVVM, Clean Architecture, and Jetpack Compose within multi-module architectures to create maintainable, fast, and user-focused apps that scale with user demand and business needs.

Jeffy Lazar

App Developer, Front-End Developer, Developer, +3

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Hi, I’m Jeffy Lazar, a Senior Android Developer based in Kitchener, Canada. I excel at building mission-critical mobile experiences, modernizing legacy apps, and delivering end-to-end features with a strong focus on performance and reliability. I’ve spent 9+ years crafting scalable Android architectures, mentoring teammates, and collaborating with product, design, and backend teams to ship high-quality software.\n\nI’m passionate about turning complex requirements into modular, testable code. I enjoy applying MVVM, Clean Architecture, and Jetpack Compose within multi-module architectures to create maintainable, fast, and user-focused apps that scale with user demand and business needs.…Hi, I’m Jeffy Lazar, a Senior Android Developer based in Kitchener, Canada. I excel at building mission-critical mobile experiences, modernizing legacy apps, and delivering end-to-end features with a strong focus on performance and reliability. I’ve spent 9+ years crafting scalable Android architectures, mentoring teammates, and collaborating with product, design, and backend teams to ship high-quality software.\n\nI’m passionate about turning complex requirements into modular, testable code. I enjoy applying MVVM, Clean Architecture, and Jetpack Compose within multi-module architectures to create maintainable, fast, and user-focused apps that scale with user demand and business needs.

Available to hire

Hi, I’m Jeffy Lazar, a Senior Android Developer based in Kitchener, Canada. I excel at building mission-critical mobile experiences, modernizing legacy apps, and delivering end-to-end features with a strong focus on performance and reliability. I’ve spent 9+ years crafting scalable Android architectures, mentoring teammates, and collaborating with product, design, and backend teams to ship high-quality software.\n\nI’m passionate about turning complex requirements into modular, testable code. I enjoy applying MVVM, Clean Architecture, and Jetpack Compose within multi-module architectures to create maintainable, fast, and user-focused apps that scale with user demand and business needs.

Skills

Experience Level

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Intermediate

Beginner

Language

Javanese

Advanced

English

Fluent

Work Experience

Senior Android Developer at theScore

November 1, 2020 - November 1, 2025

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.

Senior Android Developer at Cygnet Infotech Pvt Ltd

February 1, 2016 - September 1, 2020

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.

Android Developer at eProcurement Technologies

October 1, 2014 - February 1, 2016

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.