Senior Full-Stack Engineer | Frontend-leaning | Platform Team | Remote Spain

Role overview

Senior full-stack engineer joining a platform team in a frontend-leaning capacity. You will build foundational product experiences while also contributing to backend services, shared tooling, testing, and a custom design system. The position offers broad ownership over technical direction and product quality, with work that supports sophisticated financial workflows and data-heavy user experiences.

Responsibilities

- Deliver robust, maintainable, and well-tested full-stack features, with particular attention to frontend quality and user experience. - Shape frontend architecture and contribute to Node.js services, platform tooling, infrastructure-facing concerns, and the internal design system. - Collaborate with product managers, designers, QA specialists, and other engineers during discovery, design critique, feedback, and delivery. - Improve performance, reliability, maintainability, developer experience, and test coverage across the stack. - Write meaningful unit and end-to-end tests using Vitest, Playwright, or equivalent tools. - Influence platform-wide decisions, resolve complex UX cases, guide architecture and performance work, and mentor fellow engineers.

Requirements

- Five or more years of experience building product applications across the stack, with substantial frontend expertise. - Fluency in TypeScript, experience with modern frontend frameworks, and confidence contributing to Node.js backend services. - Experience with design systems, including ownership or maintenance of custom systems at senior level. - Familiarity with unit and end-to-end testing, accessible UI/UX, and building elegant, practical interfaces. - Ability to work through ambiguity, ask productive questions, and convert early concepts into shipped software. - Experience in a startup or scaleup setting, together with strong communication and collaborative problem-solving skills.

Nice to have

- Background in fintech or another highly regulated environment. - Experience with Zod or similar validation libraries. - Experience creating data visualizations, including tables and charts.

Benefits and work setup

- Remote role based in Spain, with an average quarterly trip to Berlin. - Salary plus equity and a flexible benefits package that can support wellbeing, sport, mobility, food, and related needs. - 28 vacation days, two company days, and local public holidays. - Quality technical equipment and collaboration with a diverse international engineering organization.