Senior Java Developer

Senior Backend Engineer (Java/Kotlin) We are looking for an experienced Backend Engineer to join a team building modern, scalable systems based on a microservices architecture. This role offers real influence over technical decisions, system architecture, and the quality of delivered solutions—particularly within payment and subscription platforms. Responsibilities • Design, develop, and maintain backend systems using Java or Kotlin and the Spring Framework • Build and evolve microservices following DDD, CQRS, and Hexagonal Architecture principles • Implement event-driven communication, ideally using Apache Kafka • Work with relational databases (PostgreSQL or other SQL databases) and optimize queries • Write unit and integration tests using JUnit, Mockito, and Testcontainers • Contribute to the design and development of cloud-based solutions (AWS or GCP) • Participate in code reviews and drive high engineering standards • Collaborate closely with product and engineering teams to deliver business-critical features Requirements • Strong experience with Java and/or Kotlin • Solid knowledge of Spring / Spring Boot • Hands-on experience with SQL and relational databases (preferably PostgreSQL) • Proven background in microservices-based architectures • Experience with event-driven systems (Kafka is a strong plus) • Practical experience with backend testing (JUnit, Mockito, Testcontainers) • Experience working with cloud platforms (AWS or GCP) • Good understanding of Domain-Driven Design (DDD), CQRS, and Hexagonal Architecture • Must-have: experience with payment systems and/or subscription-based platforms Nice to Have • Experience working with high-scale, high-availability systems • Knowledge of security and transactional data handling • Background in product-driven, Agile environments