Position: Senior Java Software Engineer Salary: up to 30 000 PLN Working model: hybrid from Katowice We are looking for a Senior Software Engineer for our client — a global technology organization providing large-scale, high-performance software solutions used by hundreds of thousands of users daily.The company combines strong in-house engineering expertise, advanced technology, and a people-first approach to deliver top-tier products and services.You’ll be part of a growing Tech Hub based in Katowice, collaborating closely with international teams across Europe and other global locations.The role:In this role, you will design, build, and deliver core applications that power the company’s main platform.You’ll work alongside Product Managers, Business Analysts, and QA specialists to create high-quality software, implement new features, and ensure top performance and scalability.This position is a great opportunity for someone who enjoys working in a collaborative, global environment and wants to have a real impact on key business applications.Responsibilities: Design, develop, and enhance complex software solutions Collaborate with Product, Architecture, and QA teams through all phases of SDLC Write unit and integration tests, participate in design and code reviews Develop prototypes and test programs when needed Provide technical evaluation and recommendations on key engineering decisions Offer technical guidance and mentorship to less-experienced team members Requirements: At least 5 years of experience with Java Strong knowledge of Object-Oriented Programming, principles, and design patterns Solid experience with SQL and exposure to Hibernate / JPA / Spring JDBC Proven experience building RESTful services Focus on performance and scalability optimization Familiarity with development tools such as IntelliJ, JUnit, JMeter, Maven, Jenkins, Git, Jira Ability to lead technical projects; Tech Lead experience is a plus Excellent communication and problem-solving skills, proactive and collaborative approach Nice to have: Experience working with multi-tier, asynchronous, distributed architectures Understanding of multithreading and concurrency Experience with data modeling and transformations (XML, XML Schema, XSLT) Exposure to message brokers (e.g. RabbitMQ) Knowledge of NoSQL databases (e.g. MongoDB) Cloud experience (AWS, Azure, or GCP) and containerization (Docker, Kubernetes) Understanding of network protocols and basic Unix skills The offer: Flexible form of cooperation (B2B or Employment Contract) Competitive salary and annual bonus plan Private medical care and group life insurance Hybrid work model — 2 days per week from home MyBenefit cafeteria platform and lunch vouchers Holiday allowance and paid lunch break (30 minutes) Tax-deductible costs and other financial advantages