Senior Backend Java Software Engineer

Location: Warsaw, Poland Work model: Hybrid – regular work from the Warsaw office Technology: Java, Spring, distributed systems, CI/CD, GitHub Seniority: Senior About the role We are looking for an experienced Senior Backend Software Engineer to join an international engineering team developing a large-scale E-Commerce Platform. The platform supports critical purchasing, subscription and account management processes used by customers across multiple markets. You will work on backend services responsible for high-volume, business-critical transactions where scalability, reliability and availability are essential. This is a hands-on engineering position combining software development with system design, technical investigation and collaboration with Product, Design and engineering teams. The cooperation is based on a hybrid working model, with regular presence in the company’s Warsaw office. What you'll be working on You will: Develop high-quality, scalable and reliable backend services using modern technologies.Design and develop solutions for complex, distributed systems.Write clean, efficient and maintainable code following engineering best practices.Contribute to the modernization and evolution of the platform's architecture and technology stack.Work closely with Product Managers, Designers and engineering teams across different locations.Participate in technical design and architecture discussions.Review code and provide constructive feedback to other engineers.Troubleshoot and resolve software and production issues.Contribute to automated testing and overall platform quality.Work within an Agile/Scrum development environment.Participate in the team's on-call rotation and support the resolution of production incidents. What we're looking for 5+ years of professional software development experience.Strong commercial experience with Java.Very good knowledge of the Spring ecosystem.Hands-on experience designing and developing highly scalable distributed systems.Strong system design skills.Good understanding of software engineering principles and development best practices.Experience with automated testing and modern testing frameworks.Understanding of observability, monitoring and production reliability.Ability to work independently and take ownership of technical solutions.Experience collaborating with cross-functional and international teams.Professional working proficiency in English. Nice to have Experience in the e-commerce, payments, subscriptions or transactional systems domain.Experience leading technical or cross-functional initiatives.Experience with Continuous Integration and Continuous Deployment (CI/CD).Knowledge of Jenkins Pipelines.Experience with Infrastructure as Code (IaC).Previous experience with PHP.Experience working with distributed teams across different time zones.Interest in applied AI, including AI-assisted development, agents, prompt engineering or integrating AI models into products. How you'll spend your time 40% – Software development / coding40% – Technical design & investigation15% – Meetings and collaboration5% – Documentation Engineering environment Methodology: Agile / ScrumIssue tracking: JiraKnowledge base: ConfluenceVersion control & code reviews: GitHub Working model This opportunity involves hybrid cooperation in Warsaw. The engineering team works partly from the company's Warsaw office, so we are looking for candidates who are comfortable with regular on-site presence and collaboration with the local team. If you are a Senior Backend Engineer who enjoys solving complex technical problems, designing scalable systems and working on products with significant business impact, we would be happy to hear from you.