Ostap – Android, Kotlin, Java

A sophisticated, feature-rich food ordering application serving hundreds of thousands of active users daily.

• Built and maintained the networking layer of an enterprise mobile application, improving the modularity and maintainability of the codebase;
• Implemented automated code quality checks, including static code analyzers and cloud-based solutions such as Codacy;
• Set up and maintained CI pipelines, Jacoco-based code coverage, automated UI tests, and screenshot testing;
• Implemented Design System 1.0 and contributed to the native implementation of Design System 2.0;
• Configured compile-time separation of GMS and HMS application flavors and supported their deployment to the respective app marketplaces;
• Developed and maintained features across native Kotlin and Flutter/Dart application domains.

A sophisticated and feature-rich food ordering application serving a large user base, with hundreds of thousands of daily users. The platform supports a wide range of ordering and customer-facing features designed to provide a seamless experience at scale.

• Helped transition the software architecture to a modular, multi-module structure, improving code organization and maintainability;
• Co-designed, implemented, and maintained the networking layer, including an OAuth2 authentication subsystem;
• Implemented a native design system to support consistent UI development across the application;
• Set up automated code quality controls, CI pipelines, code coverage, and UI/screenshot testing;
• Integrated the JSON: API standard to support consistent API communication and data exchange.

A mobile platform designed for small businesses to manage key day-to-day operations, including inventory, promotions, and reservations. The application provided businesses with tools to streamline operational workflows and manage customer-facing activities from a mobile device.

• Developed core business workflows in Kotlin for a chain of small businesses with complex logic and extensive process automation;
• Built functionality for inventory, sales, transaction history, and tipping operations;
• Delivered promotional and reservation features supporting daily business activities;
• Implemented virtual queue management to optimize customer flow;
• Added QR code-based menus, enabling customers to access menus directly from their mobile devices.

A mobile solution integrated with custom hardware through Bluetooth connectivity and connected to major digital payment ecosystems. The platform supported seamless interactions between mobile devices, proprietary hardware, and digital payment services, including Alipay and WeChat Pay.

• Implemented a payment subsystem and standalone application supporting secure Alipay and WeChat Pay transactions;
• Integrated custom POS hardware via Bluetooth to enable card payment acceptance;
• Supported a broad range of card payment methods, including magnetic stripe, chip, and contactless transactions;
• Enabled payment processing for various card types, including Diners Club and American Express.