Senior Full-Stack Developer (React / Node.js) (m / f / x)

osapiens; Madrid; Híbrido; EUR 70.000 - 90.000; Jornada completa

Descripción de la vacante

A tech company in Madrid is seeking a Senior Full-Stack Developer to shape the future of its Business Partner Transparency platform. This role involves designing and optimizing full-stack features, collaborating with agile teams, and ensuring high-quality code. The ideal candidate has strong experience in React.js, Node.js, and a product mindset. This position offers a hybrid work model, emphasizing collaboration and remote flexibility.

Servicios

Purpose-driven mission

Collaborative teamwork

Hybrid work options

Personal and professional growth

Sustainable mobility options

Fun team events

Inspiring workspaces

Formación

• Strong experience in full-stack development, especially with React.js, Node.js, JavaScript, and TypeScript.
• Expertise in web services development and integration.
• Excellent communication skills in English (C1).

Responsabilidades

• Design, build, and optimize full-stack features using modern technologies.
• Develop software solutions that automate compliance workflows.
• Collaborate with cross-functional teams in agile squads.
• Ensure high-quality code through reviews and testing.
• Own the architecture and design of JavaScript-based solutions.
• Identify opportunities for innovation and process improvements.
• Mentor junior developers.

Conocimientos

Full-stack development experience

React.js

Node.js

JavaScript

TypeScript

REST

GraphQL

Git

Agile workflows

Excellent communication in English

Descripción del empleo

Department: Business Partner Transparency

Employment Type: Permanent - Full Time

Location: Madrid

Description

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.

Key Responsibilities

• 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.

Skills, Knowledge and Expertise

• 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). Spanish is a bonus but not necessary.

Benefits

• 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 Madrid and beyond