MarsBased is a development agency from Barcelona offering end‐to‐end web & mobile apps built with Ruby on Rails, React and JavaScript. We believe in remote work, clean code, and delivering quality over quantityWe're looking for a senior full-stack engineer to join our Martian team, with strong knowledge of Node.Js and React.You'll be joining a small, senior, and highly-collaborative team that values autonomy, quality, and transparency. We build things the right way. We believe in doing deep, focused work — not meetings all day.If you love elegant code, solving complex problems, and being part of a kind and experienced remote team, this might be your next orbit.WHAT YOU'LL DO- Build and maintain modern, scalable web applications using Node.Js, React, and Next.Js.- Collaborate closely with clients and teammates in a friendly, remote-first environment.- Contribute to architecture decisions and ensure clean, maintainable codebases.- Use AI-assisted coding tools to improve development speed and quality.- Help us refine our internal tools, workflows, and development culture.GENERAL SKILLS- Excellent communication with clients and teammates.- Strong self-management skills for remote work.- High attention to detail.- Positive attitude towards new challenges and a fast learner.- Proactive and able to work independently on self-managed projects.- Experience using AI agents or AI code editors to assist in coding tasks.- Fluent in written and spoken Spanish.- Fluent in written and spoken English.TECH SKILLS- 5+ years of production experience building Node.Js and React applications.- Production experience with Next.Js, the App Router, and Server Components is required.- Experience with React Router or Remix (nice to have).- Strong JavaScript and TypeScript knowledge, both frontend and backend.- Solid understanding of relational databases and SQL.- Production experience deploying and maintaining Node.Js applications.- Familiar with Docker and containers in both development and production environments.- Experience with testing frameworks such as Jest or Cypress.- Ability to build scalable and maintainable software over time.- Strong writing and documentation skills, we value clarity in your code and solutions.BENEFITS- Competitive salary.- Work from home or from a coworking space.- Flexible working hours.- Amazing coworkers.- Modern tech stack and methodologies.- Transparency and quality-oriented culture.- Company activities.WHY MARSBASEDWe're a boutique agency, not a factory. We work with clients who respect our time, process, and craftsmanship. You'll be part of a senior team where your voice matters and your work has a real impact.Join us and help us build software that lasts — from Mars, or anywhere you call home