Marcos – AWS, React, Next.js

A civic-engagement platform used by public-sector organizations to manage constituent datasets running to hundreds of thousands of records. Features include an AI assistant answering questions across that data, geographic visualization and segmentation, dashboards and reporting, and Kanban-based task management, delivered on both web and mobile.

• Led the migration of major platform functionality from the web application to React Native, creating a unified cross-platform experience.
• Designed and developed AI-powered backend services using Python, FastAPI, and the OpenAI API for document analysis, semantic search, contextual assistance, and automated content generation.
• Built scalable REST APIs integrating the web application, mobile application, and external services.
• Implemented geospatial visualization features using Google Maps API and Leaflet to manage more than 200,000 voter records.
• Optimized MongoDB queries by introducing compound indexes and normalized search fields, reducing query latency by over 90%.
• Developed interactive dashboards, Kanban boards, PDF reports, spreadsheet exports, and standardized API documentation.
• Established automated testing pipelines and reusable backend architecture for multi-team scalability.

A clinical AI tool for physicians that replaces manual chart review with conversation, allowing them to ask questions about a patient's records in plain language rather than reading through them. Main features are a conversational query interface, clinical dashboards, and exportable summary documents.

• Developed the frontend application using React and TypeScript, delivering responsive interfaces optimized for clinical workflows.
• Integrated the frontend with Python FastAPI backend services and Socket.IO streaming APIs to provide real-time AI-powered conversations.
• Built reusable UI components, dashboards, charts, forms, and visualization modules that simplified access to patient information.
• Worked closely with backend engineers to define API contracts, optimize application performance, and deliver scalable AI-driven functionality.
• Implemented testing, analytics, and production optimizations to improve software reliability and user experience.

A B2B web product rebuilt from the ground up off Figma designs, covering complex forms, data tables, document generation, and location-based views.

• Rebuilt the entire frontend from Figma designs using React and TypeScript, creating reusable UI components and a scalable design system.
• Developed customer management, scheduling, proposal management, project tracking, dashboards, and reporting features to support daily business operations.
• Implemented advanced forms, filtering, searchable tables, Google Maps integration, and interactive data visualizations that simplified complex workflows.
• Integrated frontend modules with REST APIs while collaborating closely with backend engineers to ensure reliable and scalable business processes.
• Improved application quality by resolving production issues, optimizing performance, integrating PostHog analytics, and expanding automated test coverage.

An enterprise procurement platform serving more than 40,000 users, covering purchasing, supplier management, reverse auctions, and multi-stage approval workflows, with integration services keeping procurement data synchronized across connected enterprise systems. I worked across the stack on product features and owned the integration services, with most of my impact on backend and frontend performance.

• Doubled backend request throughput by optimizing SQL Server queries and API paths, validated under load with Grafana K6
• Cut frontend page load times by roughly 45% through lazy loading, memoization, and rendering optimizations
• Built event-driven backend services over RabbitMQ absorbing enterprise-scale workloads
• Delivered integration services synchronizing procurement data across enterprise systems via GraphQL
• Shipped purchasing, supplier management, auction, and approval workflow features across the stack
• Diagnosed and resolved production issues across distributed services

A mobile investment portfolio app used by retail investors to see holdings consolidated across brokers and asset classes, with live market prices, portfolio valuations, and financial indicators streaming in continuously.

• Developed frontend and backend features supporting ordering, customer engagement, payment processing, and operational management.
• Built RESTful backend APIs using Node.js, FastAPI, and PostgreSQL, integrating multiple internal and third-party business services.
• Integrated Pagar.me and Braspag payment gateways for secure payment processing and implemented Talon. One for automated promotional campaigns and coupon validation.
• Developed a Progressive Web Application with offline support, push notifications, and responsive interfaces to improve accessibility for restaurant staff.
• Applied Clean Architecture principles and implemented secure role-based access control to improve scalability, maintainability, and long-term system evolution.

A mobile investment portfolio app used by retail investors to see holdings consolidated across brokers and asset classes, with live market prices, portfolio valuations, and financial indicators streaming in continuously.

• Developed new mobile features using React Native and TypeScript for investment portfolio management.
• Designed and implemented the Bitcoin Connection feature, allowing users to integrate cryptocurrency investments into their portfolios.
• Integrated WebSocket services to deliver real-time market prices, portfolio updates, and financial indicators.
• Improved application responsiveness through optimized state management using Redux and MobX.
• Collaborated closely with UI/UX designers to transform Adobe XD designs into production-ready Android and iOS applications.

A suite of business management applications for small and mid-sized companies, covering finance, administration, customer management, and day-to-day operational workflows. Features included automated boleto generation for billing, a real estate financing simulator that calculates amortization schedules across multiple financing scenarios, and responsive web interfaces used across the whole suite.

• Developed business management applications supporting finance, administration, customer management, and operational workflows using PHP and Laravel.
• Built a real estate financing simulator capable of calculating amortization schedules across multiple financing scenarios.
• Integrated PJBank services to automate boleto generation, reducing processing time from hours to nearly instant execution.
• Developed responsive web interfaces using JavaScript and Bootstrap, improving usability across multiple business applications.
• Optimized Firebird database operations, maintained legacy applications, and collaborated directly with stakeholders to deliver customized business solutions.