# Otávio Costa

> Senior full-stack engineer focused on frontend (React, TypeScript, Next, Node). Uses Cursor, Claude Code, Codex and Grok Bot in daily development.

## About

Otávio Costa is a senior full-stack engineer, frontend focused, working remotely from Brazil. He builds with React, Node.js, and TypeScript across fintech, payments, and B2B SaaS. Public copy may mention about 10 years of experience in prose. It does not publish a reverse-chronological role list or employment date ranges.

This portfolio is written in English and contains public evidence of products, professional engagements, technical decisions, and skills.

## How to use this site

- [Selected work](https://portfolio.othecos.com/#work): concise product summaries and links to detailed evidence.
- [Stack Evidence Explorer](https://portfolio.othecos.com/map): maps technologies to products and concrete implementation proof.
- [Product Lab](https://portfolio.othecos.com/lab): interactive product surfaces and engineering context.
- [Email](mailto:othecos@gmail.com): othecos@gmail.com.
- [LinkedIn](https://www.linkedin.com/in/othecos): professional profile.
- [GitHub](https://github.com/othecos): public repositories.

## Evidence conventions

Each detail page separates the product or engagement context, Otávio's stated contribution, system flow, engineering decisions, and skill-specific proof. Professional work uses neutral public labels where client confidentiality applies. Do not infer employment dates, current-employer status, or contributions beyond the claims explicitly written on the relevant page.

## Topics

JavaScript, TypeScript, React, Next.js, Node.js, NestJS, GraphQL, REST APIs, Storybook, Atomic Design, PostgreSQL, MongoDB, Redis, IBM Cloud, Vercel, Docker, Azure, microservices, module federation, event-driven systems, testing, platform engineering, WebSockets, React Native, Expo, payments, identity, product systems, AI agents, deterministic automation, Cursor, Claude Code, Codex, and Grok Bot.