Senior Ruby on Rails Developer (LLM)

OnTheGoSystems

📍 Barcelona, Catalonia, Spain

Full time Computer Occupations

Job Description

Senior Ruby on Rails Developer 

We are looking for a senior Ruby on Rails developer to help us build reliable, scalable products and apply AI/LLM technologies where they create real value.

This is a hands-on engineering role for someone who can own complex features end to end, make strong technical decisions, and work across backend architecture, production systems, testing, and AI-assisted product development.

You should be excited about AI, but pragmatic enough to know when a simple, deterministic solution is better than an LLM call.

What you’ll be working on:

  • Owning features from technical design to production
  • Building and maintaining Ruby on Rails systems used at scale
  • Designing AI/LLM-assisted features and workflows where they improve product quality or user experience
  • Working with LLM APIs, prompts, retrieval/context strategies, and AI-assisted development tools
  • Making trade-offs around p...
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