srmrqaz

Location: Mar del Plata, Argentina (UTC-3)
Remote: Yes
Willing to relocate: No
Technologies: Ruby on Rails, JavaScript, React, PostgreSQL, Hotwire, TypeScript (personal projects), APIs, AI-assisted development
Resume/CV: https://smarquez1.github.io/assets/Sergio-Marquez-Resume.pdf
Email: [email protected]
Website: https://smarquez1.github.io/
I'm a hands-on senior software and product engineer who has built production web applications since 2011. Rails is my deepest specialization, alongside substantial JavaScript and React experience. I work across APIs, PostgreSQL, integrations, testing, and performance, and like working with users and a small team from problem discovery through implementation.
In my current role, I work with school founders and teachers on a Rails product for their day-to-day operations, from discovery through implementation. I also shipped an LLM-powered task generator that lets teachers review and edit the results. Previously, at Decisiv, I improved page-load times by 20% to 80% for affected workflows and led an incremental modernization of more than 500,000 lines of Rails code. I use Claude and Codex in my development workflow, but I review and test the work before shipping it.
I'm looking for a long-term, full-time remote senior engineering role with hands-on backend or full-stack work. I'm open to Rails, JavaScript/React, and TypeScript-based teams; the problems and the people matter more to me than a particular stack. I'm also interested in useful AI features and better developer workflows. I'm based in Argentina, comfortable working in English, and can overlap with US working hours.