Johnylab

What I do

  • AI products: LLM and RAG features from prototype to production, with an agent-assisted development workflow.
  • Full stack delivery: React, Next.js and TypeScript on the front end; Node.js, Go and Java on the back end.
  • Technical leadership: architecture, code review and mentoring in distributed teams.

Blog Insights:

I write about AI for beginners and about job hunting, in Portuguese, on my blog. Recent posts:

  1. O que aprendi enviando mais de 500 candidaturas em dois meses (com números)

    Nas últimas semanas, tratei minha busca por emprego como um...

  2. Contexto e RAG: por que a IA esquece e como fazê-la consultar seus documentos

    No post anterior vimos que um LLM prevê texto e...

  3. 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...

More insights await in the Blog Section.

About

  • Based in Santos, SP, available for remote work.
  • Brazilian, and father of three.
  • I mentor developers for free in the Agência Gift community and publish small open-source projects on GitHub.

Professional identity

  • Full stack engineer (React, TypeScript, Node.js) building AI-powered web products.
  • Open to full-time roles and selected contract work.

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.