STARLING A. GERMOSEN REYNOSO
Senior .NET / Backend Engineer — Legacy Modernization & AI Integration
Professional Summary
Senior .NET engineer with 14+ years of experience designing, modernizing, and maintaining backend systems across government, healthcare, and fintech. I specialize in taking over and revitalizing legacy applications — VB6, WinForms, and MVC migrated to modern ASP.NET Core / .NET 8 — together with REST API design and SQL performance tuning. Over the past year I have led AI integration in a production healthcare SaaS: building LLM-assisted clinical features, curating fine-tuning datasets, and engineering guardrails against model hallucination. Beyond contract work, I build and operate my own products end to end — including ResumiBot, a live multi-tenant AI SaaS integrating three LLM providers, voice, video-generation and payments into one automated pipeline. I own the full backend lifecycle, thrive in async and documentation-driven teams, and am available as an independent contractor across US and European time zones.
Core Skills
Languages & Backend: C#, .NET Core / .NET 8, ASP.NET Core, Web API, VB.NET, VB6, ADO.NET, Entity Framework Core, Dapper, SignalR, Node.js
Architecture & APIs: REST, SOAP-to-REST modernization, CQRS, Mediator, Onion / N-Layer, SOLID, API Gateway, OAuth, microservices (Azure Functions)
Databases: SQL Server, Oracle & PL/SQL, MySQL, MongoDB, SQLite — query & stored-procedure optimization
AI / ML: OpenAI, Anthropic Claude & Google Gemini integration, Azure AI, LLM fine-tuning datasets, prompt engineering, RAG, Whisper & neural TTS pipelines, local models (Llama), AI-assisted product features
Cloud & DevOps: Microsoft Azure (Functions, App Service, Storage, Notification Hubs), Docker, CI/CD (GitHub Actions, Azure DevOps), GitFlow, Hangfire, Nginx, PM2
Frontend & Mobile: Razor Pages, MVC, Blazor, JavaScript, Vue.js, Angular, Bootstrap; Xamarin, .NET MAUI, Flutter
Testing & Practices: xUnit, NUnit, Playwright, SonarQube, code review, Scrum / Kanban
Professional Experience
SolMed — Healthcare SaaS · Founder & Lead .NET Engineer / Software ArchitectJan 2025 – Present · Remote (DR)
- Architected and built a multi-tenant medical practice-management SaaS on ASP.NET Core, Razor, and SQL Server — clinical records, scheduling, electronic invoicing (DGII compliance), inventory, and payroll.
- Led AI integration across the platform: shipped OpenAI / Azure AI-assisted features that speed up clinical documentation and support physician decision-making.
- Built and curated multi-turn LLM fine-tuning datasets for "Clepio," an AI clinical assistant, and engineered anti-hallucination guardrails (explicit counterfactual constraints) that prevent fabricated diagnoses and unsafe recommendations.
- Reviewed training data at scale, detecting and correcting systematic labeling errors — contraindicated prescriptions and mismatched diagnoses — prior to fine-tuning.
- Designed the architecture for an offline, on-device AI voice assistant (local Llama model, Kotlin Multiplatform, encrypted SQLite) to operate the platform hands-free.
Product Perfect · .NET DeveloperSep 2023 – Jan 2025 · Remote (USA)
- Delivered backend and web components across the full SDLC for tax-domain applications built on .NET.
- Mentored new engineers on coding standards and GitFlow, and coordinated the team to meet delivery milestones.
BairesDev · .NET Full-Stack Developer (Contract) — NomadHealth, Place Inc., Claims ScorpMar 2022 – Apr 2023 · Remote (US)
- Migrated legacy WinForms applications to .NET 6 and a core system from .NET Framework 4.5 to .NET 7 with a Razor UI, improving performance and cutting maintenance cost.
- Developed microservices with Azure Functions, improving response times and scalability; integrated an external Python platform with a core system.
Applaudo Studios · .NET & SQL Developer (Contract) — Miami Heat, Dollarama, DollarCityOct 2021 – Mar 2022; May – Sep 2023 · Remote (US)
- Built a fraud-detection and prevention system that reduced fraudulent transactions.
- Developed a video-extraction pipeline with Hangfire; optimized SQL queries and stored procedures, improving data-retrieval and reporting performance.
MersyRD — Medical SaaS Startup · Software Architect & Full-Stack DeveloperJul 2018 – Feb 2022 · Remote (part-time)
- Led a medical-records SaaS from concept to production and migrated it MVC 4.5 → .NET Core 3.1 → .NET 6 for scalability and maintainability.
- Built a companion mobile app in Xamarin Forms; served hospitals (Darío Contreras, Vinicio Calventi) and 50+ private physicians.
DGII — Dominican Tax Authority (Government) · Software DeveloperDec 2011 – Oct 2021 · Santo Domingo
- Led the migration and modernization of the "Sucesiones y Donaciones" system: VB6 → VB.NET Web Forms → ASP.NET Core.
- Modernized data exchange from SOAP to REST across government and financial institutions.
- Migrated and tuned Oracle databases and complex queries; built and optimized the "DGII Móvil" mobile app in Xamarin Forms.
Selected Products & Projects
ResumiBot — AI WhatsApp assistant SaaSLive · resumibot.com
Founder and sole engineer of a multi-tenant SaaS that turns high-volume WhatsApp groups into AI summaries, narrated podcasts, avatar news videos and infographics. Integrates three LLM providers (OpenAI, Anthropic Claude, Google Gemini) with per-tenant BYOK keys and quota fallback, Whisper transcription, neural TTS, HeyGen/D-ID/Replicate video synthesis, FFmpeg media pipelines, PayPal subscriptions and a public REST API — Node.js orchestration with a Python media engine, deployed with PM2/Nginx and GitHub Actions CI/CD. The clearest proof of my ability to integrate many technologies into one shipped product.
LottoKing — lottery retail management platformIn production since 2021
End-to-end platform for lottery retail networks ("bancas"): ticket sales with QR/barcode and Bluetooth thermal printing, automated prize calculation across 9 game modes and 12+ lotteries (DR, NY, Haiti, Chile), risk/restriction engine, daily cash reconciliation, ~20 exportable reports and real-time SignalR monitoring. ASP.NET Core + SQL Server, multi-tenant, multi-currency; seller app in Xamarin with an in-progress .NET MAUI rewrite.
Estimat Pro — electrical-materials price comparisonLaunch-ready
Two-sided marketplace (US Hispanic market) that compares true total cost — price, state taxes, delivery, stock, distance, promotions — across suppliers, with a cart-split optimizer and QR-coded PDF purchase orders. .NET 8 clean-architecture API + Flutter app (iOS/Android/Web), bilingual ES/EN, 32 xUnit + 18 Flutter tests, Playwright E2E, complete App Store / Play Store publishing kit.
AcademicSystem — white-label school managementLive · real institution
Multi-tenant academic platform: self-enrollment with prerequisite/capacity/schedule validation, weighted grading, automated transcripts (Kardex) with GPA trends and academic-standing classification, attendance, verifiable certificates and reports — trilingual (ES/EN/FR), with JWT REST API and a .NET MAUI companion app. .NET 8, EF Core, ASP.NET Identity.
Torneo Predicciones — social sports-prediction appFunctional · iOS & Android
Prediction game rewarding accuracy (1 pt winner / 3 pts exact score) with private moderated groups and per-group leaderboards. Xamarin.Forms apps with offline SQLite cache, ASP.NET Core backend on Azure with Notification Hubs push and Facebook login; web admin panel for leagues, teams and matches.
Clepio — AI clinical assistant
LLM fine-tuning + safety guardrails, integrated into SolMed.
Amico Solution — SaaS medical-records platform
Xamarin mobile app; WinForms → .NET 4.8 migration.
Denunciado — civic-engagement platform (.NET)
Connecting municipalities with citizens.
Education
- M.A., E-Commerce — APEC University, Dominican Republic (2014)
- B.Sc., Software Engineering — UTESA University, Dominican Republic (2010)
- Teaching Qualification — UTESA University, Dominican Republic (2018)