Joan Antoni Serra Castillo

• Designed and developed an end-to-end enterprise AI ecosystem with AI-Core (.NET 9 REST API), AI-Front (Next.js 15/React 19), and AI-Agents-Semantic-Base (Orleans + Semantic Kernel).
• Led Risk Agent automation flows across n8n, LLMs, and secure API integrations, achieving a daily reduction of 8-9 hours in manual operational work.
• Engineered a scalable distributed runtime with Orleans 9.2 and Semantic Kernel, orchestrating 10+ LLM models and 40+ tools focused on fintech use cases.
• Pioneered Model Context Protocol integration over SSE with custom MCP clients and servers, enabling secure dynamic tool discovery and enterprise system connectivity.
• Implemented semantic retrieval workflows with PostgreSQL + pgvector (1536 dimensions) to improve context quality and response relevance in AI-assisted operations.
• Delivered real-time AI interfaces with streaming chat, Markdown/KaTeX rendering, and an interactive workflow editor powered by XYFlow and Redux API slices.
• Established an AI-driven SDLC workflow to convert functional requirements into production-ready code with faster delivery cycles and maintained engineering quality.
• Implemented Databricks governance workflows and n8n orchestrations connecting Salesforce, Jira, and internal APIs for auditable automation at scale.
• Co-led strategic backend migration to AKS and optimized Docker deployment patterns for highly available AI microservices.

Tech: .NET 9, ASP.NET Core, C#, Semantic Kernel, Orleans, Azure OpenAI, Anthropic, PostgreSQL/pgvector, Redis, n8n, Databricks, AKS, Docker, OpenTelemetry.

• Designed and developed scalable microservices in .NET Core and .NET Framework for a high-traffic booking engine, applying Clean Code and SOLID principles.
• Integrated Azure OpenAI and Semantic Kernel to automate extraction, transformation, and classification of unstructured data (Excel, PDF, and other sources).
• Developed internal assistants and agent-based workflows using vector stores and semantic memory to support real-time operational decisions.
• Built robust third-party integrations (REST and SOAP), transforming external data flows into stable internal domain models.
• Optimized critical SQL Server queries, reducing response times and improving throughput in core business processes.
• Collaborated closely with Product and DevOps teams under Agile/Scrum to ensure fast and reliable delivery cycles.
• Provided technical leadership to junior developers while defining backend architecture and communication/data flow patterns.
• Managed source control in Azure DevOps with GitFlow and reinforced quality through pull request reviews.

Tech: .NET Core, .NET Framework, Azure OpenAI, Semantic Kernel, Azure Service Bus, SQL Server, Azure DevOps, REST APIs, SOAP, Swagger.

• Owned development and maintenance for an ecosystem of seven interconnected applications built on .NET Framework and .NET Core.
• Improved SQL Server performance through indexing plans, query tuning, and stored procedure optimizations for high-volume business workflows.
• Designed microservices patterns to improve modularity and reduce coupling across core business capabilities and shared infrastructure concerns.
• Integrated asynchronous messaging with RabbitMQ to increase throughput and reliability in event-heavy processing pipelines.
• Implemented and maintained background services for time-critical business processing, ensuring consistent execution and operational continuity.
• Refactored and modernized legacy .NET codebases for better maintainability, compatibility, and production performance.
• Redesigned WPF desktop interfaces to improve usability and reduce friction in internal user journeys.
• Worked within Agile/Scrum methodologies with Product Managers and QA teams, using Jira to optimize delivery cycles and team coordination.
• Provided mentorship to junior developers, reinforcing best practices in backend development and software design patterns.

Tech: .NET Framework (4.7.2/4.8), .NET Core, SQL Server, RabbitMQ, WPF, Windows Services, REST APIs, SOA, PostgreSQL, Jira.

• Delivered backend solutions in .NET Core and .NET Framework focused on integrations and operational performance for business-critical systems.
• Implemented REST and SOAP APIs connecting internal platforms with Dynamics NAV 2013 and external providers.
• Optimized SQL Server and MySQL workloads with indexing and query tuning to support critical daily operations.
• Worked as a full-stack developer integrating .NET backend services with React frontend interfaces for cohesive delivery.
• Maintained and refactored legacy systems in PHP (CodeIgniter 3) and Windows Forms, preserving reliability while reducing technical debt.
• Integrated Microsoft Graph API to automate communication and productivity workflows across internal teams.
• Served as Team Lead in the final period, coordinating developers, conducting code reviews, and aligning technical execution with business requirements.
• Collaborated closely with business and product teams to align technical implementation with functional requirements and operational priorities.

Tech: .NET Core, .NET Framework, SQL Server, MySQL, REST, SOAP, React, Razor, Windows Forms, WCF, Microsoft Graph.

• Developed a WPF desktop application using the MVVM pattern, integrating SQL Server and WCF web services.
• Built a REST API with n-tier architecture and created reusable NuGet packages for modularization.
• Developed web applications using JavaScript (jQuery) inside an MVC architecture.
• Implemented client-control add-ins for Microsoft Dynamics NAV, extending ERP platform capabilities.
• Gained hands-on experience with Agile Scrum practices and collaborative multi-team delivery environments.

Tech: .NET Core 2.0, WPF, MVVM, SQL Server, WCF, REST APIs, NuGet, JavaScript (jQuery), MVC, Dynamics NAV.