Back to Portfolio
PT

Leonardo Balsalobre

Senior Software Engineer · AI-Powered Products with React, Node.js & LLMs · 10+ Years Full-Stack

Summary

Senior software engineer with 10+ years building production full-stack and AI-powered products. Specialized in React, Node.js, and TypeScript, with hands-on experience designing RAG pipelines, integrating LLMs, and shipping cloud-native systems on AWS. Frequently leads technical discussions, shapes product decisions, and mentors engineers to deliver reliable, maintainable software with measurable business impact.

Skills

React · React Native · Next.js · Node.js · Nest.js · TypeScript · JavaScript · Rust · GraphQL · REST APIs · AWS (ECS, EKS, Lambda, S3, DynamoDB) · Docker · Kubernetes · PostgreSQL · MongoDB · Redis · LLMs · Retrieval-Augmented Generation (RAG) · Prompt Engineering · AI-Assisted Development · System Design · CI/CD · Microservices · Clean Architecture

Experience

Senior Software EngineerBalsa Tech

March 2024 – Present

Remote (United States)

  • Deliver high-fidelity React and React Native products for global clients, accelerating roadmaps through AI-powered development orchestration.
  • Integrate LLMs and AI tooling into the development lifecycle to boost delivery speed and code quality.
  • Architected and implemented scalable features for a clinical-trial platform, ensuring regulatory compliance and system optimization.
  • Managed release cycles end-to-end: CI/CD pipelines, testing strategies, and deployments.
  • Architect scalable frontend solutions with React, TypeScript, and Tailwind, paired with Node.js and Rust backends on AWS.
  • Collaborate directly with international stakeholders to translate business needs into production-ready features.
  • Stack: React, React Native, Material UI, Styled Components, Next.js, GraphQL, Node.js, Nest.js, Rust, Golang, AWS (ECS, EKS, DynamoDB, SQS, S3, RDS, CloudFront), Kubernetes, Docker, DataDog, GitHub Actions.

Lead Software Engineer2K Games

December 2023 – March 2024

Remote (United States)

  • Acted as tech lead for a cross-functional team building features used by 2K Games' global player base.
  • Provided architectural guidance, set coding standards, and aligned engineering work with business goals.
  • Facilitated sprint planning and reviews, led technical discussions, and mentored junior engineers.
  • Drove the product roadmap with product owners and leadership while keeping code quality and performance on track.

Senior Full Stack Engineer2K Games

November 2022 – December 2023

Remote (San Diego, CA, United States)

  • Led development of the Portal Login Registration — 2K Games' centralized login platform serving players worldwide.
  • Coordinated with regional teams across time zones to align requirements and delivery.
  • Stack: React, Tailwind, Emotion, Contentful, Next.js, Node.js, GraphQL, Golang, Kubernetes.
  • Streamlined development by introducing best practices and Clean Code principles, improving maintainability and onboarding speed.

Senior Full Stack EngineerAWWCOR, Inc. (PatientFi)

November 2021 – December 2022

Remote (Utah, United States)

  • Contributed to PatientFi, a leading patient-financing platform used by healthcare providers nationwide.
  • Implemented new features, improved existing functionality, and ensured cross-browser/device compatibility.
  • Stack: React, Redux, Node.js, Express, Mongoose, MongoDB, TypeScript, Rust, AWS, Docker.
  • Researched and applied frontend/backend best practices to raise the bar on performance, security, and UX.

Software EngineerItaú Unibanco

January 2021 – November 2021

São Paulo, Brazil

  • Built foundational components of a Banking-as-a-Service (BaaS) platform for the largest bank in Latin America, used by millions.
  • Designed scalable, reliable infrastructure and established engineering best practices for future development.
  • Stack: Kotlin, SpringBoot, NestJS, AWS (EKS, CloudFormation, Fargate, S3), DynamoDB, Kafka, jUnit, Jest, Swagger/OpenAPI.

Lead Software EngineerNew School

February 2020 – January 2021

Brazil

  • Led a team of 4 engineers building an application that delivers free quality education to youth from underserved communities.
  • Owned the project end-to-end: infrastructure, architecture, delivery, and stakeholder communication.
  • Stack: Vue.js, Vuetify, Nuxt.js, React, Next.js, React Native, Node.js, Nest.js, TypeORM, MySQL, Docker, AWS, Jest.

Software EngineerSemantix Brasil (Unimed)

January 2019 – February 2020

Brazil

  • Led migration of Unimed Brazil's APIs to an API Gateway architecture, improving security and reliability of customer data flows.
  • Built the Angular front-end used to manage the gateway's API surface.
  • Stack: Node.js, Koa, MongoDB, Redis, Docker, Kubernetes, Angular, TypeScript, SCSS.

Software EngineerBalsa Tech

January 2016 – December 2018

Brazil

  • Provided full-stack technology consulting to Infracommerce, Kobe Software, Nutax, Dasa, Nugget.ai, and Nearix.
  • Designed and shipped tailored solutions, owning communication and delivery throughout each engagement.
  • Stack: Vue.js, React, Redux, Node.js, Nest.js, MongoDB, PostgreSQL.

Education

USP — Universidade de São PauloFebruary 2024 – November 2025

MBA, Software Engineering

Univesp2020 – 2023

Bachelor's degree, Information Technology

FATEC Santo AndréJanuary 2018 – December 2019

Electrical and Electronics Engineering

ETEC — Escola Técnica Estadual de São Paulo2016 – 2018

Electrical, Electronic and Communications Engineering Technician

Certifications

JavaScript Algorithms and Data Structures · Microservices: Design Patterns · Go (Golang): Exploring Google's Programming Language · DataDog Foundation · Advanced JavaScript

Languages

Portuguese (Native) · English (Bilingual) · Spanish (Professional Working) · Italian (Elementary)

Honors & Awards

Developer who helped most