Sainsbury's High-Scale E-Commerce & Retail

Flagship Grocery Mobile App Native Transformation

Key Android Contributor & Platform Architect • May 2018 – April 2023

Transformed one of the UK's largest online grocery shopping applications from a hybrid legacy architecture to a high-performance native Kotlin solution serving millions of active users.

Project Context & Impact

Sainsbury’s is a cornerstone of UK retail. Their digital grocery platform handles immense traffic volumes, particularly during high-demand periods like peak holiday seasons.

Key Contributions

Native Transformation: Replaced legacy hybrid/scraping layers with clean, testable native Kotlin modules, radically improving app launch times, battery consumption, and scroll performance.
Modular Multi-Module Architecture: Designed decoupled feature modules that enabled dozens of distributed engineers to build and deploy features independently without merge conflicts.
High-Volume Reliability: Implemented rigorous automated testing (JUnit, Mockito, Espresso) and performance monitoring to guarantee rock-solid stability at national scale.

Key Impact & Delivery

Re-architected core shopping journeys into a fully modular native Kotlin app using MVVM, Jetpack, and Dagger.
Eliminated legacy web scraping and brittle webviews, integrating high-throughput REST APIs and real-time basket sync.
Supported millions of weekly grocery orders with stellar crash-free session rates (> 99.8%).

Technologies Applied

Kotlin Modular MVVM Architecture Android Jetpack Dagger / Dependency Injection REST APIs CI/CD & TDD

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