Freelance Developer – Korean MMORPG (Private Server Development, Serious Engine 1)

Key Responsibilities & Achievements:

• Delivered continuous updates and enhancements for a legacy Korean MMORPG based on Serious Engine 1, collaborating with multiple private server owners to tailor game functionality.
• Modernized the game’s C++ codebase by migrating from C++98 to C++17, improving performance, maintainability, and enabling modern language constructs.
• Migrated game rendering logic from DirectX8 to DirectX9, increasing graphical stability and future-proofing the engine’s capabilities.
• Developed a set of WPF desktop applications for internal tooling, including advanced features such as model and animation rendering with DirectX11 (Virtice Lib) and custom shader support.
• Built ASP.NET Core backend services to extend server-side functionality, including modular APIs for player management, event triggers, and telemetry.
• Designed and developed a web-based administration panel (React + .NET Core) for server operators to manage game configurations, user access, and deployment processes. Implemented secure SSH integration to control remote game servers directly from the web interface.
• Built a custom game launcher using Tauri (Rust + WebView2) to handle client updates, patch delivery, news display, and game settings — later migrated to a more feature-rich WPF + WebView2 Established robust data exchange mechanisms between the website and game servers for real-time configuration syncing and monitoring.
• Provided end-to-end support to private server owners, including reverse engineering, feature customization, tooling development, and DevOps assistance.

Stack: .Net Core, ASP Core, C++, Boost, MySQL, WPF, DirectX11(C# lib)

Banking ERP System for Microloans for SMEs

Responsibilities & Achievements:

• Developed new features across frontend and backend to improve system functionality and performance.
• Refactored business logic in microservices to enhance scalability and maintainability.
• Integrated Apache Kafka for asynchronous service communication between distributed components.
• Designed and implemented a custom orchestrator class to control task execution order across services, improving reliability of complex workflows.
• Integrated and maintained GraphQL API using Apollo, enabling efficient and flexible data exchange between frontend (React) and backend (.NET Core).
• Set up CI/CD pipelines in Azure DevOps and managed environment-specific deployments.
• Created unit and integration tests to ensure system reliability and support refactoring efforts.
• Developed a reusable .NET library for Excel file parsing, used in various import scenarios.
• • Implemented a configurable cron job scheduler in ASP.NET for modular and maintainable background task execution.

Stack: MongoDB, Kafka, ASP Core, React, Azure DevOps, PostgresDB, GraphQL

A government-focused web system for monitoring the construction and financing of infrastructure projects (roads, bridges, etc.).

Responsibilities & Achievements:

• Sole mid-level developer on the project, working alongside and mentoring a junior developer.
• Improved the access control system with fine-grained permission checks down to database tables and individual records.
• Implemented core business logic based on customer requirements; added metrics and application health monitoring.
• Integrated Diia.ID for secure state-level user authentication.
• Configured and utilized Elasticsearch for fast and flexible data search.
• Developed a parser for ATU (Administrative-Territorial Units) structure to support region-based access and reporting.
• • Wrote unit and integration tests to ensure system reliability

Stack: .Net Core, ASP Core, VueJS, Quasar Framework, JS, Rancher

A healthcare platform integrated with eHealth, the national electronic health system enabling secure exchange of medical data and support for government-backed medical services.

Responsibilities & Achievements:

• Developed core business logic for managing medical data, documents, and user workflows in compliance with eHealth standards.
• Implemented digital file signing using both USB token-based keys and file-based keys, ensuring legal validity and security of medical documents.
• Integrated system components with eHealth APIs for seamless data exchange and alignment with national healthcare regulations.
• Added application metrics and monitoring capabilities to track performance and system health.

Stack: .Net Core, ASP Core, VueJS, Quasar Framework, JS, Rancher

A government portal for the online submission, processing, and tracking of licensing applications related to pharmaceutical activities.

Responsibilities:

• Implemented business logic for licensing workflows, including applications for: Manufacturing of medicines , Import of medicinal products, Pharmacy production and wholesale/retail trade
• Worked on backend tasks under guidance from senior developers, ensuring compliance with regulatory requirements.
• Participated in bug fixing, feature development, and integration of new business rules into the existing codebase.

Stack: .Net Core, ASP Core, VueJS, Quasar Framework, JS, Rancher

A system focused on complex automation of enterprises oSQL Development and CRM/ERP System Enhancements in IT Enterprise Responsibilities:

• Extensive SQL development to support and expand the company’s CRM/ERP system

• Optimization of the enterprise and reengineering of business processes in order to solve problems aimed at achieving the strategic business goals of the enterprise.

• Transitioning legacy code from Visual FoxPro to C# for better performance and maintainabilityr groups of enterprises.

Stack: .Net Framework, MSSQL, VisualFox Pro