You will take ownership of a backend system that is critical to the company and our customers. You will have the opportunity to help define our roadmap and find the best technical solutions. You will also have time to run some experiments and bring new ideas to the table.
Your responsibilities: Hands-on code implementation, code reviews, testing
Ensure reliability, performance and correctness.
Diagnose and resolve complex production issues.
Collaboration with other engineering & Product teams.
Make pragmatic decisions balancing risk, maintainability, and business needs.
Improve code quality and internal structure where possible.
What we are looking for: 5 years plus experience building and maintaining production systems as backend engineer




Strong experience with Ruby on Rails
AI-first mindset using tools like Cursor, Claude Code, Codex, in your daily workflow
Working on large-scale products
Experience owning systems that are business critical.
Methodical approach to debugging and problem solving.
Comfortable working autonomously with high ownership.
Advanced level of English.
Tech Stack: Language & Platform: Ruby
Data: PostgreSQL or Redis
Infrastructure: Tailwind
Location: Barcelona, Spain >
or Fully remote within a +/- 4hrs CET
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📌 Senior Backend Engineer - Ruby On Rails (Barcelona)
🏢 Ersilia
📍 Barcelona