Romualdo Santos
Verified Expert in Engineering
Software Engineer and Developer
Bragança Paulista - State of São Paulo, Brazil
Toptal member since July 14, 2026
Romualdo is a senior software engineer with 15+ years of experience building scalable web applications, cloud-native services, and developer tools. HE specializes in JavaScript/TypeScript, Node.js, React, and AWS, with a proven track record of delivering high-impact products for startups and enterprise clients. Romualdo has strong expertise in system design, performance optimization, and product development, thriving in autonomous, remote-first teams.
Portfolio
Experience
- Amazon Web Services (AWS) - 15 years
- JavaScript - 15 years
- Node.js - 12 years
- TypeScript - 10 years
- React - 9 years
- Next.js - 5 years
- Tailwind CSS - 4 years
- Shadcn UI - 2 years
Preferred Environment
MacOS, Node.js, TypeScript, JavaScript, React, Next.js, Amazon Web Services (AWS)
The most amazing...
...work I've done is turning complex ideas into production-ready products—from cloud-native platforms to enterprise-scale applications.
Work Experience
Lead/Senior Software Engineer
Lumenalta
- Architected and developed full-stack features for a large-scale asset management platform using React, Node.js, GraphQL, AWS, and Terraform.
- Designed and delivered a complex benchmarking and analytics experience, collaborating across teams while building reusable, scalable React components.
- Designed and implemented a unified GraphQL-powered search platform spanning multiple financial domains with ranking, autocomplete, and permission-aware filtering.
- Resolved a long-standing performance bottleneck by redesigning back-end architecture and SQL queries, reducing response times from minutes to seconds.
- Identified and fixed a critical financial data integrity issue by redesigning complex SQL and GraphQL query logic.
- Designed a secure document delivery workflow using AWS S3 pre-signed URLs, improving security and user experience for large financial datasets.
- Built highly interactive financial data visualizations and dashboards, transforming complex datasets into intuitive insights for portfolio managers.
- Designed reusable front-end architecture and shared component libraries, accelerating feature delivery while improving consistency and maintainability across applications.
- Designed and implemented scalable GraphQL APIs and back-end services, integrating multiple internal and third-party financial data sources.
- Led technical improvements across CI/CD, automated testing, and code quality, increasing deployment reliability and maintainability for a large engineering organization.
Senior Software Engineer
Truelogic
- Built white-label ordering platforms powering multiple restaurant brands from a shared codebase, maximizing reuse while supporting brand-specific customization.
- Designed and implemented a custom GraphQL ordering platform, replacing 3rd-party dependencies with a scalable in-house solution.
- Delivered pixel-perfect, high-performance customer experiences for major NYC restaurant brands, collaborating with Frog's award-winning product and engineering teams.
Lead/Senior Software Engineer
Ci&T
- Led the architecture and delivery of large-scale healthcare and telemedicine platforms, enabling secure, real-time services with high availability and cloud-native infrastructure.
- Designed event-driven microservices architectures and distributed systems across AWS and GCP, leveraging Kubernetes, messaging, and cloud services to build resilient, scalable applications.
- Architected and modernized enterprise web platforms across healthcare, eCommerce, legal, and financial domains, improving scalability, maintainability, and development velocity through modern front- and back-end architectures.
- Led modernization initiatives that transformed legacy applications into scalable, maintainable platforms, improving engineering velocity, reliability, and long-term product evolution.
- Progressed from Junior Developer to Technical Lead while architecting and delivering mission-critical platforms across healthcare, telemedicine, eCommerce, legal, and financial industries.
Intern/Junior Software Developer
Formatta Negocios
- Built expertise in back-end development, relational databases, and enterprise application architecture through hands-on work across Jakarta EE, Spring, ETL, and integration projects.
- Developed business-critical ERP modules and data processing pipelines using Java technologies, SQL, and web services, supporting enterprise operations.
- Progressed from trainee to Software Developer while building enterprise ERP systems and ETL solutions, establishing a strong foundation in software engineering.
Experience
PDF Viewer that Works Everywhere
https://www.pdfli.co/homeBrazilian NF-e XML to DANFE PDF Converter
https://www.minhadanfe.com.br/DevDeck
https://github.com/romajs/dev-deckEducation
Bachelor's Degree in Computer Science
UNESP – São Paulo State University, Júlio de Mesquita Filho - Rio Claro, São Paulo, Brazil
Skills
Libraries/APIs
React, Node.js, Stripe, Ramda
Tools
Shadcn UI, GitHub, Sentry, Claude, Jenkins
Languages
JavaScript, CSS, TypeScript, HTML, Python, Java, Scala, Delphi, SQL, GraphQL, Swift
Frameworks
Next.js, Tailwind CSS, Material UI, Express.js, Koa, Spring Boot, JSF, Jakarta Server Pages (JSP), Angular
Platforms
Amazon Web Services (AWS), Vercel, OpenVidu, AWS IoT, Google Cloud Platform (GCP), AWS Lambda, Java EE (Jakarta EE), MacOS, Docker
Storage
PostgreSQL, Database Management, Redis, Amazon S3 (AWS S3)
Paradigms
Microservices, Continuous Delivery (CD), DevOps, Scrum, Agile, Kanban, Object-oriented Programming (OOP), REST
Other
API Integration, APIs, Authentication, Full-stack, Cloud Storage, Full-stack Development, OpenAI, Solution Architecture, Supabase, Design Systems, Lovable, Progressive Web Applications (PWAs), Prompt Engineering, Supabase Auth, CI/CD Pipelines, React Hooks, Serverless, Software Engineering, Network Systems, Compilers, Programming, ECS, Amazon RDS, PCI Compliance, HIPAA, HIPAA Electronic Data Interchange (EDI)
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