Java Developer – Billing Systems (REF5676S)

Join a team responsible for one of the most business-critical areas within Deutsche Telekom's international group: billing systems . We deliver accurate, reliable, and flexibly configurable billing for fixed-line and mobile networks as well as mobile service providers — serving millions of customers.

We're actively working to merge fixed-line and mobile billing into a single, modern platform, while gradually retiring legacy systems. That means you won't be maintaining a static, "legacy-only" system — you'll be part of a continuously evolving architecture undergoing real modernization.

Your responsibilities will include

• Developing software solutions and ensuring operational stability within an agile project setup
• Coordinating in an agile environment with the involved business units
• Analyzing and processing requirement documents
• Direct coordination with business departments and internal engineering teams
• Contributing to the implementation of new business and IT initiatives
• Analyzing and resolving production issues
• Experience with agile software development
• Java, Spring Boot
• Web technologies (e.g., JSON), with a focus on backend development
• Experience with cloud platforms (AWS, CaaS)
• Familiarity with development tools such as GitLab, Docker, Kubernetes, IntelliJ
• Experience implementing RESTful services and microservices; familiarity with TMF APIs is a plus
• Database expertise, ideally MongoDB, Oracle DB, or similar
• Frontend development experience
• Willingness to get familiar with a complex software landscape
• Python
• Experience with AI development tools
• Strong analytical and communication skills, in both written and spoken English
• German language skills are a strong plus and will make onboarding into the team significantly easier — however, they are not a hard requirement, and candidates without German are still very welcome to apply
• Work on a large-scale system modernization project within an international corporate environment
• A modern, cloud-native tech stack (AWS, Kubernetes)
• Production-grade, business-critical systems with real impact on customer experience
• A collaborative, agile team culture
• Please be informed that our remote working possibility is only available within Hungary due to European taxation regulation.