Rafael

• Outline: Led the technical design and hands-on development of scalable, cloud-native, and AI-enabled solutions for U.S. organizations. Focused on modernizing legacy systems, integrating AI/LLM capabilities, and ensuring high standards in architecture, code quality, and delivery.

• Responsibilities:

◦ Led the migration of legacy .NET Framework services to .NET 6 and Azure Web Apps.

◦ Integrated subscription services like Netflix and YouTube Premium into a customer portal.

◦ Developed and maintained legacy Windows Forms applications responsible for customer management (CRUD operations), billing generation, and financial workflows.

◦ Led the migration of core Windows Forms functionalities to a modern web architecture using React and .NET Core, improving scalability, UX, and maintainability.

◦ Implemented an on-call support service with Datadog for monitoring and incident response.

◦ Standardized AI-assisted development workflows using Cursor

• Outline: Part-time engagement on an enterprise AI research platform (chat-based RAG over private document corpora). Focused on the Python/LangChain orchestration layer, multiprovider LLM integration, and end-to-end telemetry, integrating a React/Next.js chat front end with AI backend services.

• Responsibilities:

o Built end-to-end LLM telemetry for LangChain/LangGraph pipelines: per-model latency, step-level traces and stacktraces, input/output token accounting and cost attribution per request.

o Implemented RAG orchestration across multiple providers (Anthropic Claude, OpenAI, Mistral), with routing and fallback decoupling model choice from application code.

o Developed semantic search and retrieval over OpenSearch — embeddings, reranking, and answer generation with source citations.

o Developed scalable Python/FastAPI backend services for chat, search, secure document access (S3 presigned URLs), and feedback persistence.

o Integrated React/Next.js chat interfaces with AI services through REST and WebSocket APIs, with Clerk-based authentication and session management.

o Optimized application performance and LLM cost using the telemetry layer, identifying slow models and retrieval bottlenecks.

• Outline: Designed and built a subscription-based EdTech platform from scratch — learning paths, recurring payments, oral assessments, and a gated community — owning architecture, data model, payments, testing, and deployment end to end.

• Responsibilities:

o Architected a full-stack application with Next.js 16 (App Router), React 19 and TypeScript, using Server Actions and a service layer for business logic.

o Designed a PostgreSQL data model with Prisma ORM (migrations, seeding) and a rolebased domain (Admin / Instructor / Student) with distinct status lifecycles.

o Built role-based access control (RBAC) with route-level middleware protection and NextAuth (credentials + Discord OAuth2).

o Integrated Asaas payments with recurring PIX and credit card, covering the full subscription lifecycle via webhooks, automatic expiration (cron jobs), and cancellation flows.

o Integrated third-party services — Discord (OAuth2 + bot) for community access, Resend for transactional email, Vimeo for video delivery — and PDF generation for completion certificates.

o Implemented ~90 automated tests across unit (Vitest), integration (Vitest + PostgreSQL) and end-to-end (Playwright) layers, covering auth, RBAC, payments and full user journeys.

o Containerized app and databases with Docker (multi-stage build, separate dev/test databases), automating migrations and seeding on deploy.

o Built a consistent design system with Tailwind CSS 4, Radix UI / shadcn/ui, and typesafe forms with React Hook Form + Zod.

o Standardized AI-assisted development workflows (Claude Code / Cursor) for code generation, review, and testing

• Outline: Contributed to the development of a large-scale SaaS platform, focusing on an AIpowered visual testing product to detect visual regressions and UI defects.

• Responsibilities:

◦ Designed and implemented scalable backend services using Node.js and AWS serverless architecture.

◦ Developed responsive and user-centric frontend interfaces with React and TypeScript.

◦ Ensured code quality and system reliability through comprehensive testing and CI/CD pipelines.

• Outline: Led the modernization of the “Resgate Express” financial platform, migrating it to a distributed microservices architecture to improve scalability, performance, and maintainability.

• Responsibilities:

◦ Led a squad of five engineers, owning technical decisions and mentoring team members.

◦ Redesigned the system from .NET Framework to a .NET Core-based microservices architecture.

◦ Implemented RabbitMQ for asynchronous communication and published domain events to Kafka.

◦ Ensured system resilience with fault-tolerance mechanisms.

• Outline: Contributed to the development of mission-critical financial products focused on liquidity, credit, and investment flexibility for XP clients.

• Responsibilities:

◦ Developed and evolved services for anticipating investment redemptions and providing dynamic credit limits.

◦ Developed backend services using .NET and Node.js with a focus on clean architecture and microservices.

◦ Integrated systems using asynchronous messaging and event-driven patterns.

• Outline: Led the technology strategy of the startup, overseeing architecture, hiring, and delivery across mobile, backend, and web platforms. The platform reached over 20,000 users with 10% paying subscribers.

• Responsibilities:

◦ Migrated legacy PHP systems to .NET Core and modernized the mobile app to Ionic 6.

◦ Implemented an offline-first architecture for the mobile app.

◦ Created full CI/CD pipelines for automated builds and deployments.

◦ Built monitoring dashboards with Datadog.

• Outline: Promoted to Tech Lead, leading a team of mobile developers and spearheading the development of the web-based back-office portal.

• Responsibilities:

◦ Led a team of two full-stack mobile developers.

◦ Architected new features and coordinated full-stack delivery.

◦ Maintained the legacy backend while preparing for the .NET Core migration.

• Outline: As the first developer, built the MVP of the Construa App, including the mobile application and backend services.

• Responsibilities:

◦ Built the mobile application in Ionic 3 for Android and iOS.

◦ Developed the backend using Laravel, including subscription logic for in-app purchases.

◦ Created core features like a civil construction knowledge base and offline access.

• Outline: Developed and enhanced features for a large-scale educational management platform, working on a DDD-based, microservices architecture.

• Responsibilities:

◦ Worked on a microservices architecture using .NET Core and Angular.

◦ Built Node.js AWS Lambda functions for report generation.

◦ Implemented asynchronous processing with RabbitMQ and Hangfire.

• Outline: Acted as Scrum Master and contributed to an ERP modernization project, an Elearning platform, and a payroll loan mobile application.

• Responsibilities:

◦ Worked on ERP modules using Zend Framework and Angular.

◦ Led the development of a custom E-learning platform.

◦ Developed a payroll loan mobile app with features like facial recognition and digital signatures.

• Outline: Developed and maintained enterprise systems including ERP modules, customer registration workflows, billing processes, desktop applications, web platforms, and mobile solutions. Contributed to the modernization of internal systems and integration with external partners.

• Responsibilities:

◦ Developed and maintained web systems, Windows Forms systems, and mobile apps using C#, ASP.NET, Angular, and Ionic.

◦ Integrated the ERP with external systems via C# Web Services.

◦ Created a product catalog app and institutional websites.