Kayo Souza

Full Stack Developer

I'm a Frontend-focused Full Stack Developer with over 8 years of hands-on experience building scalable web applications with React.js, Next.js, TypeScript, and Node.js. I have delivered high-performance interfaces and full stack solutions across different industries. I also volunteered at Brainly, where I created tools that automated content moderation on the platform.

Languages and tools

Experience

Front-End Developer

Estúdio Haus · Montes Claros, MG, Brazil · Remote

April/2024 — Present

Developed responsive web applications using React.js and Next.js, improving Lighthouse performance score from 55 to 98 on mobile.
Built reusable UI components with Tailwind CSS, Styled-Components, and Material UI (MUI).
Implemented secure authentication flows with access and refresh tokens.
Integrated REST APIs using Next.js Server Functions and resolved production CORS and browser compatibility issues.
Developed CI/CD pipelines on Azure and collaborated in Agile (Scrum) processes.

LLM AI Trainer

Revelo · Miami, FL, USA · Remote

December/2025 — Present

Evaluated AI-generated outputs for technical accuracy across TypeScript, Python, Java, and Go.
Provided structured feedback on code quality and correctness.
Designed prompts from real technical scenarios to guide LLM refinement and alignment.

Full Stack Developer

Suporte Leilões · Montes Claros, MG, Brazil · Remote

September/2023 — December/2025

Developed full stack features using PHP, Symfony, Vue.js, and Twig.
Built a CLI automation tool reducing manual tasks by up to 15 minutes per operation.
Created scripts for ERP data processing using RegExp.
Built and maintained API endpoints for frontend integration.