Johnylab

Hello there! I'm João Ferreira

Brazilian, father of three, and a software engineer since 2003.

Get in touch LinkedIn

Tech Expertise:

  • Software engineer since 2003, now focused on full stack and AI products.
  • React, Next.js and TypeScript on the front end; Node.js, Go and Java on the back end.
  • LLM and RAG features in production, plus agent-assisted development (Claude Code, Cursor, Copilot, Windsurf).
  • Problem-solving enthusiast, team player, and responsibility taker.

Blog Insights:

Explore the tech universe through my blog (in Portuguese). Recent posts include:

  1. O que é um LLM e por que a IA inventa coisas com tanta confiança

    Todo mundo fala de IA, mas pouca gente explica o...

  2. 5 Mitos de Entrevistas de Emprego Que Você Precisa Conhecer

    As entrevistas de emprego são desafiadoras, mas desmistificar alguns mitos...

  3. Ubuntu e a Cultura Organizacional Moderna

    Das Comunidades Rurais aos Empreendimentos Globais: Os Paralelos entre a...

More insights await in the Blog Section.

About Me:

  • Based in Santos, SP.
  • Brazilian, and father of three.

Professional Identity:

  • Full Stack Engineer (React, TypeScript, Node.js) building AI-powered web products.
  • Currently considering new opportunities to contribute and grow.
João at Google Space at São Paulo, Brazil

Career Summary:

Freelance Full Stack Engineer / AI Consultant (September 2025 - present):

  • Building LLM- and RAG-based web applications for startups (Pump, Arancia) with an agent-assisted development workflow.

Dappier (August 2024 - September 2025):

  • Full Stack Engineer owning the front end of an AI-agent platform and contributing to its Go API; hardened an embeddable AI-agent widget to run across third-party sites.

GoDaddy (April 2024 - August 2024):

  • Software Engineer on the website builder and e-commerce platform, including generative-AI assistance in the merchant editing flow.

Ender (August 2022 - December 2023):

  • Senior Frontend Engineer leading front-end work in a distributed team with React JS, Typescript, Node.js and AWS.
  • Engaged in testing with Playwright and GitHub automated test integrations.

FourSquare (March 2021 - July 2022):

  • Fullstack Engineer involved in web development using Ruby, Rails, Java, React JS, and AWS.
  • Worked on large and complex analytics reports applications with CI/CD stack integration.

Webnets Soluções (September 2017 - September 2020):

  • Front-end Leader overseeing the restructuring of project architectures.
  • Introduced knowledge of SPA, PWA, and REST APIs to the company.

Colégio Objetivo Baixada Santista (March 2010 - September 2017):

  • Web Developer contributing to various projects, including a video player for distance learning and educational applications.

Fundação Lusíada (June 2008 - March 2010):

  • Web Designer involved in the development and optimization of the commercial part of the website.

Escola Aprendiz (February 2007 - November 2007):

  • Teacher and Web designer teaching basic computing and web design.

More details can be found on my LinkedIn.