I am a Software Development & Management Engineer specializing in Backend & Full-Stack solutions. My engineering philosophy centers on writing clean, scalable code under SOLID & OOP principles while transforming complex business requirements into high-performance web and mobile platforms.

I’ve spent the last few years modernizing legacy architectures, automating operations, and integrating artificial intelligence to drive digital transformation. I am also deepening my cloud expertise with programs like AWS re/Start (preparing for Cloud Practitioner) and the Google Cloud Computing Foundations Academy to design resilient, cloud-native infrastructures.

• Legacy Modernization (Grand Velas): Migrated a monolithic procedural PHP legacy system to a clean MVC architecture using SOLID and OOP principles, boosting system maintainability and scalability by 45%.
• Process Automation: Developed Linux cron jobs and backend synchronization pipelines that automated daily reporting workflows, eliminating 1 to 2 hours of manual operations daily.
• Database & API Optimization (Le Blanc): Redesigned backend APIs and optimized database schemas, reducing query response times by 20% and improving inventory operational efficiency by 15%.
• Threat Detection AI (Lumi Guardian AI): Built secure RESTful API endpoints and backend flows using NestJS and PostgreSQL to power an autonomous cybersecurity assistant, resulting in a 25% increase in threat detection capabilities.

Here is a curated selection of my engineering work, highlighting architectural patterns, system efficiencies, and production-level implementations:

• Role: Backend Developer (Open Source Colaborator)
• Stack: NestJS | TypeScript | PostgreSQL | Prisma ORM | Docker
• The Impact: Contributed backend services for an autonomous AI-driven assistant designed to secure VPS environments, increasing threat detection accuracy by 25%. Used clean layered architecture to structure robust endpoints and ensure safe, asynchronous database interactions.
• Code: GitHub Repository

• Role: Full-Stack Developer (Professional Internship)
• Stack: Node.js | PHP | MySQL | JWT | Linux Cron Jobs | Gemini AI
• The Impact: Successfully migrated a legacy procedural PHP monolith to clean MVC patterns, resolving critical code complexity and boosting future maintainability by 45%. Integrated custom Linux cron pipelines to automate daily reports, saving hotel operators up to 2 hours of manual data synchronization every single day.
• Code: GitHub Repository

• Role: Lead Full-Stack Developer (Academic Project)
• Stack: Node.js | Express | PostgreSQL (PostGIS) | Flutter | Gemini AI
• The Impact: Designed and implemented a multiplatform mobile and web application mapping geospatial regional analytics. Powered backend database operations utilizing PostGIS for mapping spatial layers and connected RESTful data pipelines to Google's Gemini AI API to provide smart weather forecasts and interactive chatbots.
• Code: GitHub Repository

• Role: IT Intern & Fullstack Developer (Professional Practice)
• Stack: PHP REST API | Flutter | MySQL | Firebase Realtime DB
• The Impact: Developed an enterprise internal inventory management system. Optimized API response pipelines and restructured relational database layouts, accelerating general operational system response speeds by 20% and improving physical inventory tracking efficiency by 15%.
• Code: GitHub Repository

• Role: Full-Stack & IoT Developer (Academic Project)
• Stack: Flutter | Firebase | PayPal Payment API | IoT Sensors (ESP32)
• The Impact: Built an end-to-end cloud-connected smart parking application. Interfaced real-time IoT hardware sensors to stream occupancy states via Firebase, allowing direct payment processing. This integration increased parking spot discoverability and operational efficiency by 39%.
• Code: GitHub Repository

• DevOps: Mastering CI/CD pipelines (GitHub Actions), infrastructure as code (IaC), and container orchestration.
• Cloud Architecture: Designing cloud architectures utilizing my AWS Certified Cloud Practitioner & Google Cloud Computing Foundations credentials to build resilient, serverless, and auto-scaling systems.
• Advanced Patterns: Studying system design scalability, microservices, and event-driven architectures.

I'm always looking for opportunities to collaborate on open-source codebases, join global digital teams, or work on challenging backend problems.

• 💬 Let's talk about: Backend architectures, Node.js/NestJS, SQL performance, and cloud migrations.
• 📧 Direct Contact: david.087.hdz@gmail.com
• 💼 LinkedIn: david-hernandez-dev
• 🎓 Credly Badges: My Certifications Profile
• 🌐 Portafolio: David Chavarría Dev