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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 · 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 2025 – 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.
  • Architect scalable frontend solutions with React, TypeScript, and Tailwind, paired with Node.js backends on AWS.
  • Collaborate directly with international stakeholders to translate business needs into production-ready features.

Senior Software EngineerCurebase

March 2024 – March 2025

Remote (United States)

  • 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.
  • Stack: React, Material UI, Styled Components, Next.js, GraphQL, Node.js, Nest.js, 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, 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