At IONOS, the leading European provider of cloud infrastructure, cloud services and hosting services, you will work together with a wide range of teams. We are characterized by open structures, a friendly working culture and flat hierarchies with a strong team spirit. We firmly believe that work and fun are compatible, and offer you the right environment for this. Our constant growth means that we are always looking for new colleagues. Become part of IONOS and grow with us. We are seeking an experienced Senior Software Developer to join our Managed Kubernetes team. You'll play a crucial role in developing and maintaining our Managed Kubernetes Product that serves both internal IONOS teams and external customers. This position requires significant experience with Kubernetes architecture and a strong focus on the operational aspects aligned with CKA (Certified Kubernetes Administrator) principles. Tasks Design, develop, and maintain cloud-native applications in Golang (Kubernetes Operators, REST APIs, libraries). Architect and implement new features to enhance our Managed Kubernetes offering. Contribute to the evolution of our service architecture and infrastructure as code practices. Develop and maintain the complete DevOps toolchain (Helm Charts, GitHub Actions, GitOps workflows). Create and maintain Kubernetes operators, controllers, and Custom Resource Definitions (CRDs). Implement monitoring, alerting, and observability solutions for Kubernetes workloads; Collaborate with cross-functional teams to improve platform reliability and performance. Qualifications 5 years of hands-on experience working with Kubernetes in production environments. Strong proficiency in Golang development with a track record of delivering production-grade code; Experience with public cloud providers (AWS, GCP, Azure) or private cloud infrastructure. Deep understanding of Kubernetes architecture, API resources, and extension patterns; Proficiency with Helm and other Kubernetes package management tools. Experience designing and implementing Kubernetes operators and controllers; Expertise in container orchestration, networking, and security principles. Experience with observability stacks (Prometheus, Grafana, Loki, etc.) for monitoring and troubleshooting. Advanced Linux system administration skills; Strong knowledge of CI/CD pipelines and GitOps workflows. Nice-to-have: Kubernetes certifications (CKA, CKAD, CKS). Experience with infrastructure automation tools (Terraform, Ansible). Experience with multi-cluster and multi-tenant Kubernetes architectures. Contributions to open-source Kubernetes ecosystem projects. Benefits Hybrid working model with home office option. Flexible working hours through trust-based working hours. At some locations a subsidized canteen and various free drinks. Modern office space with very good transport connections. Various employee discounts for activities and products. Employee events such as summer and winter parties, as well as workshops. Numerous training and development opportunities. Various health offers, such as sports and health courses. About IONOS IONOS is the leading European digitalization partner for small and medium-sized businesses (SMB). The company serves around six million customers and operates across 18 markets in Europe and North America, with its services being accessible worldwide. With its Web Presence & Productivity portfolio, IONOS acts as a 'one-stop shop' for all digitalization needs: from domains and web hosting to classic website builders and do-it-yourself solutions, from e-commerce to online marketing tools. In addition, the company offers Cloud Solutions to enterprises who are looking to move to the cloud as their businesses evolve. We value diversity and welcome all applications - regardless of, for example, gender, nationality, ethnic or social origin, religion, disability, age as well as sexual orientation and identity, physical characteristics, marital status or any other irrelevant factor subject to applicable law.