Java Software Developer (f/m/d) Communication Platform in Karlsruhe

Hinterm Hauptbahnhof 3-5, 76137 Karlsruhe

About IONOS

At IONOS, we don't just manage servers – we shape the digital future for more than 6.2 million customers worldwide with our solutions. As Europe's leading hosting provider and a pioneer in independent cloud solutions, we are building next-generation infrastructure – from sovereign cloud architectures and high-performance GPU clusters to integrated AI automation tools.

What drives us is digital sovereignty for Europe and real impact for small and medium-sized businesses (SMBs) as well as large enterprises. We work in agile teams, rely on transparent structures, and believe that excellence and innovation only emerge through true team spirit.

Ready for your next step? Become part of IONOS and grow with us.

We build and operate the Hosting Communication Platform (HCP) and are currently developing the new Marketing Hub for the entire IONOS Group. Our microservice-based system enriches, generates, and delivers customer communications across email, SMS, push notifications, and letters. As a product-focused team, we are responsible for the evolution of our platform, the rollout across all IONOS brands, and the delivery of our new Marketing Hub ecosystem.

Tasks

• You will develop robust backend services using Java with Spring Boot and play a key role in evolving the platform and rolling it out for new brands.
• You will collaborate closely with other development teams and bring new ideas to life with a pragmatic mindset.
• You will contribute to technical design and review processes, helping us keep the platform stable and performant with your experience.
• You have knowledge of frontend technologies like React to further develop our Marketing Hub.
• Optional: Do you have experience with PHP? Our communication editor is currently PHP-based. In parallel, we are working on new modules for our Marketing Hub using React.

Qualifications

• You have solid experience in developing with Java and Spring Boot, and you’re comfortable working with APIs, distributed systems, and microservices.
• You thrive in a dynamic and open team environment, turning small ideas into meaningful features – always with the customer in mind.
• You write code that is clean, efficient, and reliable – but you’re also pragmatic when perfection isn’t possible.
• You embrace agile methodologies and enjoy collaborating with others. Communicating in English and optionally German is something you’re comfortable with.
• You’re able to understand different requirements and develop effective solutions. You work efficiently and take responsibility for your results.
• You're someone who’s interested in data and keen to measure the success of your implementations shortly after deployment.
• 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.

Application Note

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.

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