Senior Fullstack Engineer (Java/Kotlin + React)

B3 Consulting Poland is looking for a Senior Fullstack Engineer to join our team. You will work in a dynamic environment, focusing on building large-scale services and leading technical initiatives within a Scandinavian-inspired culture that values trust and open communication.

Key responsibilities

• Design flexible API contracts using an API-first approach and support external B2B partners with documentation and onboarding.
• Develop new large-scale services in a greenfield environment, integrating backend systems with modern web interfaces.
• Act as a technical leader and architectural anchor, defining coding standards and guiding the team through complex technical challenges.
• Bridge Java/Kotlin backend design with React-based frontend development to ensure seamless platform performance.

Requirements

• Extensive hands-on experience with Java or Kotlin and building scalable RESTful APIs.
• Strong proficiency in JavaScript/TypeScript and modern frontend frameworks, specifically React.
• Solid understanding of distributed systems, integration patterns, and secure authentication protocols like OAuth 2.0.
• Proven experience in technical leadership, including defining standards and translating product requirements into technical solutions.
• Advanced ability to leverage AI tools in engineering workflows and a proactive problem-solving mindset.

What we offer

• Work within a supportive Scandinavian culture built on logic, trust, and open dialogue.
• Access to tailored health and sports benefits to support your well-being.
• Opportunities for professional growth through Speed Coaching sessions.
• Participation in internal sports teams and various competitive events.