Senior Full Stack Developer (Node.js & React)

About the Role Are you a versatile engineer who thrives at the intersection of robust backend architecture and seamless frontend user experiences? We are looking for a Senior Full-Stack Engineer (Node.js & React) to join a high-caliber team building scalable, greenfield platforms from the ground up. This is a unique opportunity to own end-to-end feature development, tackle high-load data challenges, and directly influence the trajectory of a cutting-edge product. About the Client Our partner is an elite tech company building product engineering across Fintech, iGaming, and Marketing. They turn innovative ideas into high-performing engines and launch them at scale. As their exclusive recruitment partner, Lionhires manages their full-cycle talent acquisition. What You Will Do Architect and Build: Drive the end-to-end development of an in-house platform, taking new features from initial concept to deployment. Scale & Optimize: Design high-performing microservices capable of handling heavy traffic, utilizing RabbitMQ and Redis for optimal message queuing and caching. Integrate Systems: Seamlessly connect complex, third-party APIs with our proprietary Fintech solutions. Ensure Quality: Write clean, maintainable, and test-driven (TDD) code in TypeScript across both NestJS and NextJS frameworks. Collaborate Efficiently: Participate actively in an Agile/Scrum environment, contributing to bi-weekly sprints, grooming sessions, and strategic planning. What You Bring Deep Web Expertise: 5+ years of commercial web development experience, with a proven track record of delivering production-grade applications. Full-Stack Mastery: 3+ years of dedicated, commercial experience with both Node.js and React . Modern Tech Stack: Hands-on experience with TypeScript, NextJS, NestJS, Apollo, and Material UI. Data & Architecture: Strong proficiency with REST, GraphQL, WebSockets, and managing high-load SQL/NoSQL databases (specifically MySQL and MongoDB). Engineering Best Practices: A solid understanding of microservice architecture, TDD principles, and Git version control. Communication: Upper-intermediate to fluent English communication skills (written and spoken). Bonus Points For: 2+ years of hands-on experience with CI/CD pipelines, Docker, and Kubernetes. Deep familiarity with various queue brokers (RabbitMQ, Apache Kafka, etc.). What's in It for You Competitive Compensation: An attractive salary package with structured annual reviews to reward your growth. Seamless Relocation: A comprehensive relocation package covering your flights and a 2-week hotel stay to get you settled. Legal Peace of Mind: Official EU/Spain employment contract, including sponsorship and registration support for your family members. Work-Life Balance: 23 working days of annual vacation to ensure you stay refreshed and energized. Continuous Growth: Dedicated budget for professional learning, development opportunities, and partial compensation for language classes. Vibrant Culture: Team-building activities, birthday gifts, and access to an upcoming Social Club featuring over 50 events per year.