Senior Fullstack Engineer (RoR) - AA, Remote: Colombia - Costa Rica, Fulltime.

Gorilla Logic is looking for a Senior Full-Stack Software Engineer to join a client-facing product team focused on building and improving high-traffic, user-facing web experiences.

In this role, you will work across a mature Ruby on Rails monolith and React frontend, owning features from architecture and implementation through testing and production release.

You will contribute to a conversion-sensitive product experience where experimentation, measurable outcomes, and continuous iteration are central to how the team works.

You will also have the opportunity to build product capabilities powered by LLMs and online AI inference, using modern AI development techniques to reduce friction and improve the user experience.

This is a hands-on senior engineering role for someone who combines strong full-stack technical skills with a product mindset and is comfortable collaborating directly with a US-based client and cross-functional team. What You’ll Do Design, build, test, and ship full-stack product features using Ruby on Rails and React.

Work effectively within a large, established Rails monolith, safely extending existing functionality and improving the codebase as you go. Build and refine React components and user-facing experiences with attention to performance, usability, latency, and conversion.

Own features across backend, frontend, and data rather than handing work off between technical boundaries. Build product capabilities using LLMs and online AI inference, including prompting, context management, tools, and model reasoning.

Develop AI-powered text generation experiences that improve user workflows and reduce friction. Design features so their impact on product, funnel, and conversion metrics can be measured. Instrument and support experiments to evaluate product changes and inform future iterations.

Validate solutions using automated and traditional testing practices, as well as AI evals and tracing when applicable. Apply strong engineering and system design p