MARCOS VILLALBA
Senior Software Engineer
Paraguay (UTC -3) | +595 984 104 237
marcosariel.villalba@gmail.com | LinkedIn
PROFESSIONAL SUMMARY
Senior Engineer with 5+ years of experience leading teams and shipping production systems at scale. Architected a national election platform processing 1.3M+ events under live conditions. Currently building AI-powered SaaS products using Agentic LLM workflows. GCP Certified with deep expertise across the .NET stack, React, Python, and cloud-native infrastructure.
TECHNICAL SKILLS
- Backend: C#, .NET 9, Entity Framework Core, Django, Python
- Frontend: React, TypeScript, Astro, Next.js, Blazor, React Native, Flutter
- Cloud & DevOps: GCP (Certified), AWS, Azure, Docker, Terraform
- Applied AI: LLM Integration (Gemini), Function Calling, Dynamic Context Injection, Multi-Modal Pipelines
- Data: PostgreSQL, Databricks, Firebase
PROFESSIONAL EXPERIENCE
Senior .NET Developer
Kubikware | Remote (US)
July 2025 - Present
- Stack: React, .NET 9, Azure
- Cut login latency by 60% by refactoring legacy Redux Saga authentication to Context API + Azure B2C.
- Accelerated roadmap by 1 month by building a strongly-typed Databricks query engine with automated serialization, simplifying query code and improving maintainability.
Team Lead & Senior .NET Developer
Forty AU | Remote (US)
January 2024 - July 2025
- Stack: React PWA, .NET, Django, Python, React Native
- Promoted to Team Lead in 8 months (first Paraguayan office developer to achieve this), leading a 6-person cross-functional team (Dev + QA).
- Architected a high-concurrency Web Push Notification engine using .NET Hosted Services, integrating AWS EventBridge Scheduler to handle precise, timezone-aware delivery for 350+ hospital partners.
- Ensured the stability and reliability of a $1M+/month payment pipeline integrating Stripe, Dwolla, and PandaDoc in Django.
- Managed production infrastructure via Terraform on GCP.
- Established engineering standards for React PWA + .NET Backend, improving code consistency and review efficiency across the team.
Lead Engineer & Architect
Election Statistics Platform (Concertación) | Part-Time Contractor
December 2022 - April 2023
- Stack: .NET 6, React, Firebase, Azure
- Led emergency recovery of national election platform during live vote counting. Redesigned failing single-worker architecture to distributed micro-batching system (18 workers, 1K event batches) in 20 minutes, ensuring complete data capture across 1.3M+ events.
- Built sub-second fuzzy search across 4.7M voter records using Levenshtein Distance + Span memory optimization.
- Delivered end-to-end Mobile App, Backend API, and Analytics Dashboard in 4 months under strict election deadlines.
Technical Lead & PM
Creadores
April 2021 - December 2023
- Stack: C#, .NET 6, Flutter, Blazor
- Shipped 6+ production products including real-time Grocery Delivery (Flutter/WebSockets) and Cattle Auction platform (Blazor/.NET).
- Dual-hatted as PM (2022+): Managed client stakeholders while maintaining hands-on ownership of critical backend features.
PROJECTS (AI & SAAS)
AI Hotel Concierge (SaaS Prototype)
January 2026 | Stack: Astro, React, Gemini, Cloudflare
- Engineered agentic workflows using Gemini Function Calling to autonomously query databases and confirm bookings via WhatsApp.
- Architected a multi-tenant system that ensures strict data isolation and custom prompt contexts for each hotel client.
Mente Imparable (GenAI PWA)
July 2025 - December 2025 | Stack: Astro SSR, Google Chirp TTS, Firebase
- Built an offline-first meditation app with personalized audio generation using Google Chirp.
- Engineered a Dynamic Context Pipeline to inject user goals and versioned "Brain" prompts via feature flags.
EDUCATION & CERTIFICATIONS
- Professional Cloud Architect - Google Cloud Platform (2025)
- Mechatronics Engineer - Facultad de Ingeniería de la Universidad Nacional de Asunción (2021)
LANGUAGES
- English: Fluent
- Spanish: Native