Joan Antoni Serra Castillo

• Architected and shipped a full enterprise AI ecosystem (EON): AI-Core (.NET 10, 5-microservice platform with .NET Aspire), AI-Front (Next.js 15 / React 19), and AI-Agents-Semantic-Base (Orleans 9.2 + Semantic Kernel) — owning backend, frontend, infrastructure, and IDE tooling end-to-end.
• Built EON IDE from scratch as sole creator: a VS Code extension and a JetBrains plugin (Kotlin), both featuring a full agent loop with 12 tools, streaming chat, diff review, Microsoft Entra ID auth, and telemetry — supporting Claude and GPT models via Azure AI Foundry.
• Designed and deployed the MCP Internal platform: a multi-service gateway (10 microservices — Databricks, Salesforce, GraphQL, Grafana, Excel, Freshdesk, Jira, Back-Office, Widget) behind a YARP reverse proxy, running in a single Docker container with supervisord. Sole architect of the migration from monolith to modular gateway.
• Led the full AKS migration of AI-Core, Chat Heap, and Eon Apps: Dockerfiles, Bitbucket Pipelines, Helm charts, ArgoCD GitOps manifests, SOPS-encrypted secrets, NATS stream CRDs, UAMI/Key Vault integration, and Liquibase migrations with Entra ID authentication.
• Designed the event-driven messaging backbone using NATS JetStream: defined streams (FLOWS, AGENTS, CHATS, HIL) and consumer groups across the Orchestrator, Workers, and API layers — with exactly-once semantics via Redis idempotency.
• Engineered the Core.Orchestrator: a stateless decider workflow engine with event sourcing, saga compensation (LIFO rollback), human-in-the-loop approvals, distributed timers, and 10 node types — backed by PostgreSQL and Redis.
• Led Risk Agent automation flows across n8n, LLMs, and secure API integrations, delivering a daily reduction of 8-9 hours in manual operational work for the Risk team.
• Built and maintained 40+ agentic tools covering fintech domains: transactions, blacklist compliance, Salesforce CRM, Jira/Freshdesk ticketing, Databricks analytics, document export (PDF/Excel/Word), and semantic retrieval via PostgreSQL + pgvector.
• Implemented the full MCP Salesforce service (SOQL pagination, metadata, Excel export) and MCP Databricks service (background catalog discovery, SP auth, column-level metadata) as primary engineer.
• Managed IaC with Terraform across DEV/STG/PRO/PRO-PCI environments (80+ components), provisioning AKS, ACR, Key Vault, Front Door, Service Bus, CosmosDB, and MongoDB Atlas.

Tech: .NET 10, C#, ASP.NET Core, .NET Aspire, Orleans 9.2, Semantic Kernel, NATS JetStream, YARP, SignalR, TypeScript, Kotlin, Next.js 15, React 19, PostgreSQL/pgvector, Redis, Azure (AKS, Key Vault, Blob, ACR, Front Door), Docker, Helm, ArgoCD, Terraform, SOPS, OpenTelemetry, Azure AI Foundry, Anthropic Claude, Azure OpenAI.

• 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.