Middle Fullstack Engineer (Kotlin&React)

Xebia is a global AI-first, digital transformation, and engineering partner. With over 25 years of experience and a team of 5,000 professionals across 16 countries, we help organizations design and build scalable products, platforms, and data-driven solutions. We specialize in Artificial Intelligence, Data and Cloud, Intelligent Automation, and Digital Products, combining deep technical expertise with a strong focus on engineering excellence and a people-first culture. In the CEE region, we’re a team of nearly 1,000 experts delivering modern applications, data platforms, and AI solutions for clients such as Millennium, ING, Play, Edenred, Arabian Drilling, FedEx, Leroy Merlin, Truecaller, Volotea, Schmitz Cargobull, and many, many more. You will be: developing and enhancing microservices using Java and Kotlin, designing, developing, and modifying REST APIs and backend mocks, building web components, purchase flows, and registration processes using React, working across both backend and frontend areas, adapting to changing project needs, integrating solutions with external business partners and supporting partner-facing functionalities, collaborating with the team to deliver new features quickly and efficiently, contributing to the continuous improvement of the product and technical solutions. Your profile: 3+ years of commercial experience in software development, good knowledge of Java and Kotlin , practical experience working with microservice architecture, hands-on experience with React and modern JavaScript, good knowledge of HTML and CSS, solid understanding of REST API design and consumption, practical experience working with JSON, willingness to work across both backend and frontend development, practical experience using AI-powered assistants (e.g. Claude Code, GitHub Copilot, Cursor) to improve productivity, quality, or decision-making in software delivery, ability to quickly switch between different technological areas and tasks, good communication and collaboration skills, English at min. B2 level, Polish at min. B1 level, openness to occasional visits to the Warsaw office (1-2 days per quarter). Work from the European Union region and a work permit are required. Nice to have: experience with Docker and CI/CD processes, particularly GitLab CI, experience working with cloud environments, understanding of UX/UI principles, familiarity with Responsive Web Design (RWD), experience integrating with external partner systems, experience applying GenAI in a more structured way within the SDLC, including defined workflows, prompt patterns, or tool integrations embedded into daily work, interest in and familiarity with emerging AI-driven practices (e.g. agent-based workflows, automation patterns, AI-augmented development), with a willingness to explore and experiment beyond standard approaches. Recruitment Process: CV review – HR call – Technical Interview – Client Interview – Decision