Oscar P.

Top Rated Freelancer | Senior .NET Engineer | API Integrations | Legacy Modernization | AI-Assisted Automation Software architect with 20+ years designing and delivering enterprise systems for US and international clients. Specializes in .NET/ASP.NET Core platforms, ERP and enterprise integration architecture (QAD Adaptive, Epicor Kinetic, Workday, Amazon SP-API), and the modernization of business-critical systems into API-driven solutions. Has led modernizations that preserved decades of embedded business logic while moving platforms onto current stacks, including a 100+ GB database migration and enterprise-wide conversions to C#/.NET. Now architecting AI-driven automation on top of ERP platforms, connecting transactional systems to AI services and analytics. I started my career working with Visual FoxPro and desktop-based enterprise applications. CORE TECHNICAL SKILLS Architecture & Integration: Solution architecture · REST & SOAP API design · Enterprise system integration · Integration patterns (Hub-and-Spoke, Message Queue, Pub/Sub) · Middleware design · OAuth 2.0 · Dell Boomi · QXtend Enterprise Platforms: QAD Adaptive ERP (Adaptive UX 2.26) · Epicor Kinetic / 10.x (BAQs, BPMs, Service Connect, REST APIs) · Workday · SuccessFactors · PeopleSoft · Amazon SP-API / MWS · eBay API Backend: C# · .NET 9 / ASP.NET Core · Web API · Entity Framework Core · ASP.NET MVC · WinForms · Blazor · Serilog · Node.js /Next.js Data: Microsoft SQL Server (T-SQL, stored procedures, query optimization) · PostgreSQL · Oracle · MySQL · Data modeling · ETL /SSIS · Large-scale data migration · Power BI Embedded (App Owns Data, Row-Level Security) AI Engineering: Anthropic Claude API · AI-driven automation and data pipelines · agent-based workflows · local LLM deployment (Ollama) for cost and data-privacy control · AI-assisted development Cloud & DevOps: Azure (Key Vault, Private Link, App Service, certificate-based auth) · Docker · CI/CD · Git branching strategies (develop/UAT/production) · IIS & Windows Server production deployments Modernization: Legacy assessment · incremental migration strategy · business-logic preservation · API bridging between legacy and modern stacks Methodologies: Agile/Scrum · Sprint planning · Code review · Technical leadership · Requirements analysis How AI adds value to my work AI-assisted development for faster debugging, refactoring, and optimization Using AI tools to improve reporting, data interpretation, and business insights Supporting automation workflows with AI-driven analysis Enhancing legacy systems with modern, intelligent components Recent work highlights Migrated legacy Visual FoxPro applications to C# and ASP.NET with SQL Server backends Integrated payroll and HR platforms (ADP, Workday) with custom ERP systems Designed and implemented RESTful APIs for multi-system environments Applied automation and AI-assisted tools to reduce manual processes Led small development teams on long-term enterprise projects Others Technical Skills Tools: SSIS, Inno Setup, InstallShield I am a reliable, detail-oriented professional who values clean code, clear communication, and long-term collaboration.