Senior Ruby on Rails Developer
OnTheGoSystems
Barcelona, Spain
4 days ago
Role details
Contract type
Permanent contract Employment type
Full-time (> 32 hours) Working hours
Regular working hours Languages
EnglishJob location
Remote
Barcelona, Spain
Tech stack
Artificial Intelligence
Amazon Web Services (AWS)
Automation of Tests
Software Quality
Databases
Continuous Integration
Software Debugging
Software Architecture
Ruby on Rails
Search Technologies
WordPress
React
Large Language Models
Reliability of Systems
Backend
Api Design
Job description
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
Requirements
Do you have experience in WordPress?, Do you have a Master's degree?, 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
Benefits & conditions
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.