Senior Full-Stack Developer - React / Node.js - Business Partner Transparency (m/w/d)

At osapiens, we are committed to empowering businesses economically while promoting human rights and establishing ecologically sustainable and responsible corporate governance as a global standard.

We support global enterprises in over 60 countries in integrating sustainability and positioning themselves for the future. To achieve this, we develop comprehensive SaaS solutions that create transparency and sustainable growth across the entire value chain, meet ESG requirements, and automate manual processes.As a Senior Full-Stack Developer, you’ll play a key role in shaping the future of Business Partner Transparency (BPT) within our osapiens HUB. This enterprise-grade platform helps companies comply with critical ESG regulations like: 

• The German Supply Chain Due Diligence Act (LkSG) – ensuring suppliers uphold human rights and environmental standards.
• The Whistleblower Directive – providing secure, anonymous reporting channels.
• The Corporate Sustainability Due Diligence Directive (CSDDD) – upcoming EU-wide sustainability compliance.

Our osapiens HUB is a modern, enterprise-grade development platform that enables businesses to build powerful applications without worrying about infrastructure, scaling, or failover. You’ll help develop and refine this cutting-edge, serverless ecosystem while delivering meaningful solutions for international clients. 

This role is based in Madrid where you'll collaborate with a talented, forward-thinking team. We embrace a hybrid work model, with three days a week in the office, ensuring the perfect balance between in-person collaboration and remote flexibility. 

• Design, build, and optimize full-stack features using modern front-end and back-end technologies, ensuring scalability and maintainability.
• Develop and enhance innovative software solutions that automate complex compliance workflows for businesses of all sizes.
• Collaborate closely with product managers, designers, and engineers in small, agile squads (5-7 people) to define, refine, and implement features.
• Ensure high-quality, secure, and efficient code through rigorous reviews, automated testing, and continuous integration/deployment (CI/CD) practices.
• Own the architecture and design of JavaScript-based solutions, optimizing for performance, reliability, and user experience.
• Contribute to technical strategy and decision-making, identifying opportunities for innovation and process improvements.
• Mentor and support junior developers, fostering a culture of learning and technical excellence within the team.

• Strong experience in full-stack development with a focus on React.js, Node.js, JavaScript, and TypeScript.
• Expertise in web services development and integration (REST, GraphQL, etc.).
• Familiarity with Git for version control and collaboration.
• Strong product mindset – you think beyond code, considering user experience, business impact, and scalability.
• Agile experience – comfortable working in sprints, participating in stand-ups, and iterating quickly.
• Excellent communication skills in English (C1). German is a bonus (B1+)

• A purpose-driven mission with and for global industry pioneers in tackling complex challenges
• Room for creativity through collaborative teamwork and an open communication culture
• Flexibility and team bonding with our hybrid work options
• Fuel for your growth journey, both personally and professionally
• Sustainable mobility options, promoting eco-friendly commuting solutions
• Fun team events and outings with our global teams
• Inspiring workspaces in Mannheim and beyond