Senior Full-Stack Engineer (Node.js/React)

About the client:

A German Sustainable Tech Unicorn that is redefining how global corporations handle transparency. Backed by a €130M Series C investment, our client has built a proprietary, serverless cloud infrastructure to ensure human rights and ecological responsibility across global supply chains.

Currently in a massive consolidation phase, their Madrid Hub is expanding from 20 to over 100 top-tier engineers in 2026. This is your chance to join a high-growth environment where engineering quality and product ownership are the top priorities.

The Mission: Impact at Scale

As a Senior Full-Stack Engineer you will be an architect of transparency. You will own the end-to-end development of products that help over 2,000 global companies comply with critical ESG regulations (LkSG, CSDDD).

Key Responsibilities:

• System Architecture: Design and optimize scalable full-stack features, focusing on robust backend systems and high-performance frontend interfaces.
• Infrastructure Innovation: Work directly on a custom-built, serverless cloud ecosystem (the Hub).
• Technical Leadership: Influence the design of core libraries and microservices architecture used worldwide.
• Collaborative Strategy: Work in high-density agile squads (4-6 people) alongside tech leads to define the product roadmap.
• Quality Advocacy: Drive technical excellence through rigorous code reviews, automated testing, and CI/CD best practices.

Your Profile:e

• Experience: 6+ years of professional experience in Full-Stack development, specifically within product-based companies (no agencies or consultancies).
• Backend Mastery: Expert-level command of Node.js and TypeScript .
• Frontend Proficiency: Strong experience with React.js .
• Architecture Mindset: Deep understanding of microservices, end-to-end product ownership, and scalable design patterns.
• Communication: Fluent English (C1). Spanish is a plus but not mandatory for technical collaboration.

What’s in it for you?

• Unlimited Growth: Join a unicorn at the peak of its global expansion with a direct line to leadership.
• Good Salary Package
• Hybrid Work: A balanced model of 3 days in the Madrid office / 2 days remote
• Premium Benefits: €80/month via Thanksben + up to €200/month for transport and meals.
• High-Performance Culture: A world-class engineering team where technical decisions are made by developers, for developers.