We are seeking a Senior Backend Engineer to join a fast-growing fintech company and play a key role in scaling innovative payment solutions. If you're passionate about writing clean, efficient code and enjoy collaborating in a dynamic team, this role is for you!About E-Frontiers: We are a recruitment agency specialized in IT and engineering profiles of Irish origin, with a presence in Spain for the past 10 years. The hiring will be directly with the client, and we will support you throughout the selection process. We work with various clients, from start-ups to multinationals.Key Responsibilities:Develop, deploy, and maintain web-based applications, primarily using Ruby on Rails (experience with other languages like JavaScript, Elixir, Kotlin, Java, or Python is valued).Contribute to technical and architectural decisions, ensuring high-quality solutions.Collaborate closely with cross-functional teams and take ownership of key product developments.What We're Looking For:5+ years of experience as a Backend Engineer with Ruby.Solid knowledge of OOP, TDD, and agile methodologies (functional programming and DDD are a plus).Strong English communication skills.What We Offer:Hybrid (Barcelona) or remote work setup.Relocation and work visa support for Barcelona.23 vacation days + 2 additional days per year.Professional development, health insurance discounts, and a flexible benefits plan.Salary: 50 – 70K (based on years of experience).