Full-Stack Engineer - AI Platform (m/f/d)

Join our high-velocity AI Speedboat team as a Full-Stack Engineer!

We build AI-native products transforming fitness businesses across Europe, the US, and the UK. You’ll own end-to-end AI solutions—from backend services to user-facing interfaces—in a small, autonomous team shipping real products to real customers.

Salary range: 22,000 - 26,000 PLN net + VAT B2B

Your position in our team

Backend (Java)

• Build and maintain Java services powering our AI platform, APIs, data pipelines, and ERP integrations
• Develop LLM orchestration, context management, and conversation state handling for our Nexus agent
• Implement authentication, rate limiting, cost optimization, and observability tooling

Frontend (React / TypeScript)

• Build chat widgets, dashboards, and self-service tools for the AI agent
• Integrate AI features into Magicline interfaces for a seamless user experience
• Enable analytics, workflow builders, audience segmentation, and campaign tools

Your profile

• 5+ years building production web apps with strong backend (Java/Spring Boot) and frontend (React/TypeScript) skills
• Experience with real-time interfaces (WebSockets, SSE, polling) and modern state management (MobX, Redux)
• Comfortable with web fundamentals: HTTP, REST APIs, responsive design, and component libraries (MUI or similar)
• Skilled at writing automated tests and maintaining high code quality
• Strong collaboration skills; you thrive in cross-functional teams
• Fluent English (C1); German is a plus

Nice to have

• Exposure to AI/ML products, chat interfaces, or data visualization libraries (D3, Recharts)
• Knowledge of accessibility standards (WCAG), internationalization, B2B SaaS, ERP, or CRM
• Understanding of prompt engineering, agent frameworks, or AI observability

Your benefits with us

• Benefits package – private medical care and a sports card to support your health and well-being
• Flexible working hours – manage your schedule and enjoy a real work-life balance
• Flexible work model – work fully remotely or combine it with on-site collaboration at our modern office in Warsaw
• Flexible employment options – choose the type of contract that best suits your needs
• Access to Udemy Business – grow your skills with thousands of high-quality online courses
• Unique experience in the Fitness and SaaS industry – join a market-leading company in a dynamic, fast-growing field
• International team – collaborate with talented colleagues from around the world in a diverse and inclusive environment
• Unforgettable company events – take part in engaging team-building activities and memorable celebrations
• No dress code – express your personal style and feel comfortable at work