Senior Ruby on Rails Engineer

Posted Yesterday
Be an Early Applicant
Hiring Remotely in Spain
Remote
Senior level
Artificial Intelligence • Machine Learning • Natural Language Processing • Software
The Role
Own and deliver end-to-end backend features in Ruby on Rails at scale. Design and implement AI/LLM-assisted workflows, ensure performance, reliability, security, and maintainability. Write and maintain unit, integration, and E2E tests, debug production issues, and improve system reliability.
Summary Generated by Built In

Senior Ruby on Rails Engineer 

We are looking for a Senior Ruby on Rails Engineer 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 performance, reliability, cost, latency, security, and maintainability
  • Writing and maintaining automated tests, including unit, integration, and E2E tests
  • Debugging production issues and improving system reliability

What we’re looking for:

To succeed in this role, you’ll have:

  • Strong professional experience with Ruby on Rails, ideally at senior level
  • Experience building and running production systems used by real customers
  • Strong backend skills, including databases, API design, performance, background jobs, and security;
  • Ability to break down ambiguous problems and propose practical technical solutions
  • Hands-on interest or experience with AI/LLM technologies, 
  • Good judgment about when to use AI and when simpler engineering approaches are better
  • Strong testing habits and care for long-term code quality
  • A responsible, curious, flexible mindset: willing to debug, deploy, investigate, learn, and own outcomes

Nice to have: 

  • Experience with React
  • CI/CD, background jobs, or AWS experience
  • Experience building AI-powered product features in production
  • Familiarity with embeddings, vector search, RAG, evals, or LLM observability
  • Experience with text-processing, localization, translation, or multilingual products

Why Join OTGS?
  • Stable & self-funded: Founded in 2007, profitable, and independent.
  • Industry leaders: Creators of WPML, the #1 multilingual plugin for WordPress, used on 1.5M+ sites
  • Fully remote, async-friendly: Work from anywhere within EMEA hours
  • Engineering-driven culture: Ownership, autonomy, testing, and thoughtful problem-solving
  • Fair compensation and great benefits: Designed to support your well-being both inside and outside of work.

Want to make a lasting impact on a product used by thousands of real customers? We would love to hear from you.


 

Skills Required

  • Strong professional experience with Ruby on Rails
  • Experience building and running production systems used by real customers
  • Strong backend skills including databases, API design, performance, background jobs, and security
  • Ability to break down ambiguous problems and propose practical technical solutions
  • Hands-on interest or experience with AI/LLM technologies
  • Experience working with LLM APIs, prompts, retrieval/context strategies
  • Writing and maintaining automated tests, including unit, integration, and E2E tests
  • Responsible, curious, flexible mindset; willing to debug, deploy, investigate, learn, and own outcomes
  • Experience with React
  • CI/CD, background jobs, or AWS experience
  • Experience building AI-powered product features in production
  • Familiarity with embeddings, vector search, RAG, evals, or LLM observability
  • Experience with text-processing, localization, translation, or multilingual products
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The Company
110 Employees
Year Founded: 2007

What We Do

OnTheGoSystems is a fully remote software development company specializing in localization and translation tools, including the popular WordPress plugins WPML and Toolset. The company harnesses AI, machine learning, and algorithms to create affordable, cutting-edge tools that help businesses of all sizes go global. Operating as a multilingual and multicultural team, it focuses on providing intuitive solutions for developers and website owners without relying on external investors.

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