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

WebHosting; Karlsruhe; Hybrid; EUR 80,000 - 110,000; Full time

Job summary

IONOS is seeking a skilled backend developer to build robust Java/Spring Boot services and help evolve the Marketing Hub across brands. You will collaborate with multiple teams and contribute to design decisions to keep the platform stable and performant.

Proficiency with React for frontend integration is beneficial, and experience with APIs and microservices is valued. Strong English communication is required, with German optional in this international team.

Qualifications

• Strong backend experience with Java and Spring Boot.
• Good knowledge of React for frontend integration.
• Experience with APIs, distributed systems and microservices.
• English communication; German language optional.

Responsibilities

• Develop robust backend services using Java with Spring Boot.
• Collaborate with other development teams to roll out new brands.
• Contribute to technical design and reviews for platform stability.
• Work with frontend technologies like React to extend Marketing Hub.
• Apply agile methodologies and communicate in English; German optional.

Skills

Java

Spring Boot

React

APIs

Distributed systems

Microservices

English

German

Job description

Job Description

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 usingJava with Spring Bootand 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 likeReactto 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 ourMarketing Hubusing React.
• You have solid experience in developing withJava and Spring Boot, and you’re comfortable working with APIs, distributed systems, and microservices.
• You embrace agile methodologies and enjoy collaborating with others. Communicating inEnglishand optionally German is something you’re comfortable with.

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.