About

I’m Franklin Javier, a Principal Engineer with 16 years of front-end development experience, delivering high-performance web and mobile applications. I combine technical expertise with leadership, driving front-end and agentic engineering initiatives across product teams.

Today most of my work is AI-native. I design agent harnesses and orchestration - the skills, evaluation loops and guardrails that make coding agents reliable enough to ship with - across Claude Code, Cursor, Codex and Gemini CLI. This site is built the same way: every page has a markdown twin served through content negotiation, plus an llms.txt guide, so agents can read it as well as browsers can.

The rest of my specialization is React and Node.js architectures, web performance and observability, design systems and web accessibility (a11y). My day-to-day stack includes React, TypeScript, Remix, Node.js, and Tailwind CSS.

Experience

  • Principal Engineer at Stone Giant Studio (2023 - Present)
  • Principal Engineer at Grupo Boticário (2021 - 2023)
  • Head of Technology at Beleza na Web (2018 - 2020)

Beyond technical work, I actively contribute to the front-end community through mentorship, pair programming, and knowledge-sharing. I also speak at tech talks and on podcasts - every appearance is listed, with its original link, on the speaking page.

Open source

I publish work in the open, including projects focused on AI. Most recently stonegiantstudio/skills, a set of Apache-2.0 skills for AI coding agents, portable across Claude Code, Cursor, Codex and Gemini CLI.

Older and still in production: storefront, the Node.js and Redis boilerplate we standardised on for e-commerce. It runs the Beleza na Web and Grupo Boticário storefronts, and holds over 1M requests per minute. My other repositories are at github.com/franklinjavier.

I’m based in Lisbon, Portugal, and I write on this site in both English and Portuguese about front-end development, React, performance, and engineering culture. You can read my articles on the blog, see my talks and podcast appearances, download my CV, or get in touch.