Denys – Python, Golang, PostgreSQL

A large-scale GIS platform for processing geospatial data from multiple heterogeneous input sources in real time, secured with fine-grained, location-based access control.

• Designed and implemented features for the ingest pipeline of a highload GIS system, handling multiple input data sources and geo-based authorization.
• Integrated observability metrics and created unit tests to ensure system reliability and performance.
• Prepared and maintained technical documentation for implemented services and features.
• Managed deployments using Kubernetes and Helm charts, ensuring stable releases and rollbacks.
• Designed and implemented several desktop applications using Python for Windows environments.
• Set up CI pipelines to automatically build and deliver desktop application binaries to end clients.
• Integrated with multiple third‑party APIs to extend system functionality and data sources.
• Implemented parsers for custom binary protocols to support specialized data exchange.

A data platform for building ELT data pipelines, focused on simple configuration, high performance, and broad connector coverage across 600+ sources and destinations such as APIs, databases, files, data lakes, and warehouses.

• Implemented and maintained integrations with multiple third-party APIs as data sources and destinations.​
• Developed and extended custom connectors using Python, Docker, and Airbyte configuration formats.​
• Wrote unit and integration tests to ensure reliability and correctness of data synchronization.​
• Migrated selected API-based connectors to the low-code connector framework to speed up development.​
• Contributed improvements and fixes to the Airbyte Python SDK used for building connectors.

A large online grocery delivery platform operating in both B2C and B2B models, allowing customers to order products from multiple supermarkets with real-time pricing, stock visibility, and flexible delivery slots. The service supports scheduled deliveries with weight limits suitable for bulk orders and provides continuous support throughout the order lifecycle, from placement and picking to shipment and delivery.

• Designed and implemented multiple back-end features for the core ordering and delivery flows.​
• Wrote unit, integration, and end-to-end tests to ensure reliability and prevent regressions.​
• Set up Kafka consumers and publishers using asynchronous Python APIs for event-driven communication.​
• Integrated with Nova Poshta and other third-party services to support outsourced delivery options.​
• Participated in splitting a monolithic API into smaller microservices to improve scalability and maintainability.​
• Migrated legacy Python 2 codebase to Python 3 while preserving functionality and stability.​
• Investigated and fixed issues in the XMPP messaging channel used for real-time communication.​
• Identified a vendor library bug tied to a specific Python version and proposed a stable workaround.

A product company building and operating multiple web platforms that connect students with academic experts for on-demand help and long-term tutoring support. The ecosystem includes customer and tutor portals with personal dashboards to manage requirements, order details, pricing, payments, deadlines, and file attachments, enabling a full cycle of request, matching, delivery, and post-delivery support

• Designed and implemented features for the ingest pipeline of a highload GIS system, handling multiple input data sources and geo-based authorization.​
• Integrated observability metrics and created unit tests to ensure system reliability and performance.​
• Prepared and maintained technical documentation for implemented services and features.​
• Managed deployments using Kubernetes and Helm charts, ensuring stable releases and rollbacks.​
• Designed and implemented several desktop applications using Python for Windows environments.​
• Set up CI pipelines to automatically build and deliver desktop application binaries to end clients.​
• Integrated with multiple third-party APIs to extend system functionality and data sources.​
• Implemented parsers for custom binary protocols to support specialized data exchange.​