LeoVegas Polska seeks a Backend Engineer for their Retention team. Responsibilities include building scalable, robust, and efficient solutions within a microservice architecture using Java and Kotlin. The role involves collaboration across teams, driving initiatives, ensuring scalability, and working with technologies like Kafka, Spring, and JPA. The team develops tools for omnichannel player communication, covering areas like registration, verification, bonuses, and live sessions. The ideal candidate will have 5+ years of backend development experience with Java and Kotlin, experience with messaging tools and microservices, and familiarity with SQL databases.