Senior Full-Stack Software Engineer & IT Consultant | Enterprise Web, Mobile & Desktop Solutions

Welcome to my official GitHub Organization and Portfolio. I am a self-taught Full-Stack Architect and IT Consultant with over two decades of hands-on experience building enterprise-grade software.

By combining my academic background in Commerce with my technical mastery, I bridge the gap between complex business logic and modern software architecture. From migrating legacy ERPs to the cloud, building real-time WebSocket fleet trackers, to engineering cross-platform mobile approval workflows, my focus is always the same: delivering high-performance, scalable solutions that solve real business problems.

This space serves as a curated showcase of my professional work, highlighting clean-slate repositories, architectural case studies, and client-ready codebases.

As a full-stack engineer and consultant, I architect systems from the database all the way to the mobile device in the user's hand.

• Software Architecture: Clean Architecture, CQRS, Microservices, Systems Integration, Full SDLC
• Web & Frontend: React.js, Redux, Next.js, Blazor Server, WebSockets (Real-Time Telemetry)
• Mobile Development: React Native, Expo, .NET MAUI, Xamarin
• Desktop & Backend Engine: C#, .NET Core, TypeScript, Hono, DevExpress (XAF, MAUI, WinForms)
• Data & Cloud: Microsoft SQL Server, Appwrite (BaaS), SQLite, Firebase, Google Workspace APIs

(Reviewers: Please explore the highlighted projects below for detailed architectural breakdowns of systems I have designed and deployed from the ground up.)

Untethered executives from desktop ERPs by building a comprehensive mobile approval workflow system.

• Architecture: Securely bridged on-premise legacy databases (SQL Server) with modern cloud infrastructure (Appwrite).
• Tech Stack: React Native, Expo, TypeScript, Hono, Appwrite, C# / .NET Sync Engine.
• Highlight: Developed a custom C# background synchronization console that autonomously replicates local SQL Server records to the cloud database without disrupting legacy daily operations.

An end-to-end agricultural management platform designed to track farm assets, crop lifecycles, and field operations.

• Architecture: Bridged a robust back-office web portal with a companion, offline-capable mobile application for on-site farm management.
• Tech Stack: C#, .NET MAUI, Blazor Server, DevExpress XAF, SQLite.
• Highlight: Designed complex relational business models to track physical farm operations (planting to harvest) and pushed data to mobile devices for field workers using local SQLite databases.

A comprehensive, real-time web application designed to monitor and manage logistics fleets and assets.

• Architecture: High-performance Single Page Application (SPA) handling high-frequency, live-updating telemetry data without UI freezing.
• Tech Stack: React.js, Redux, WebSockets, REST APIs, Interactive Mapping.
• Highlight: Implemented WebSocket integrations to stream live GPS coordinates, vehicle speeds, and engine statuses directly to a dynamic map dashboard with zero latency.

Architected and developed a full-scale Enterprise Resource Planning (ERP) and Logistics system from the ground up for a major transport and hauling enterprise.

• Architecture: Centralized operations, complex financial accounting, and fleet maintenance into a single, cohesive desktop platform.
• Tech Stack: C#, .NET Framework, DevExpress XAF, DevExpress XPO / ORM, Microsoft SQL Server.
• Highlight: Automated complex payroll structures by integrating raw biometric time-logs and computing variable trip-based trucker pay seamlessly into the General Ledger.

Engineered a secure, automated background service to ensure disaster recovery compliance by syncing local enterprise backups to cloud storage.

• Tech Stack: C#, Windows Services, Google Drive API v3, OAuth 2.0, WinForms, NLog.
• Highlight: Built an autonomous Windows Service that runs invisibly in the background, utilizing OAuth 2.0 to securely stream large database payloads to Google Drive.

I am currently open to consulting opportunities, architecture reviews, and full-time/contract engineering roles.

If you are a hiring manager or client reviewing this portfolio, I would be happy to walk you through the codebase of any of these projects on a brief technical call to demonstrate my architecture and code quality.

• Email: renee.llup@gmail.com
• LinkedIn: linkedin.com/in/renee-llup-576229250
• Website / Services: https://www.renee-llup.com

Note: Some repositories in this organization may be private to protect active client IP. If we are currently in discussions, please provide your GitHub username so I can grant you secure, read-only access to specific source code.