Senior Software Developer (Java Application Developer) at DeutscheTelekomITSolutionsSlovakia

PURPOSE Develops new and maintains existing applications using modern technologies (primarily Java) based on requirements of internal or external customers. These applications support automation and transformation of business-critical processes within the Telekom domain. Works independently or as part of a project team on designing, developing, and building mid-size to complex, scalable applications in a cloud-native, microservices-based environment. As part of the role, actively contributes to the migration of business logic from a legacy billing system (one of the top 100 most critical Telekom applications) into a modern streaming platform built on Quarkus and Kafka, designed to process millions of events daily.   TEAM AND PROJECT DESCRIPTION As part of a team of experienced senior developers, you will contribute to our initiative focused on migrating business logic from a legacy billing system, currently one of the top 100 most critical Telekom applications into a modern Quarkus-based streaming platform. The new solution is built on a microservice architecture, with services communicating via Kafka, and is designed to process millions of events daily. This transformation plays a key role in modernizing core Telekom systems and improving scalability and performance.                                                                       WHAT WILL YOU DO?   • Collaborate with stakeholders (business, product, architects) to understand requirements and translate them into scalable technical solutions • Design and develop backend applications and microservices in a cloud-native environment • Contribute to the migration of business logic from a legacy billing system into a modern event-driven architecture (Quarkus + Kafka) • Design and implement REST APIs and event-driven communication between services • Analyze requirements and propose robust, maintainable architecture solutions with focus on scalability and performance • Estimate development effort, plan implementation, and support delivery planning • Develop high-quality, clean, and testable code using Java (preferably Java 17) • Ensure code quality through testing, reviews, and best practices • Participate in CI/CD pipelines, deployments, and release management • Support application operation (L2/L3), including troubleshooting, bug fixing, and performance optimization • Create and maintain technical documentation (architecture, APIs, flows) • Ensure security and compliance with internal standards • Proactively identify risks, perform root cause analysis, and drive improvements • Act as a senior team member, contributing to architecture decisions and mentoring junior developers • Share knowledge within the team and contribute to continuous improvement of development practices