Java Middleware Developer
Java Middleware Developer
(RDMI01 - Dortmund / Olpe )

The job in a nutshell

As a member of our middleware team, you will help to develop the application server of a modern open-source cloud software and expand its platform with additional microservices. This software is called OX App Suite and is one of the market-leading web applications in the e-mail environment that is used by millions of users every day. You will be part of an agile middleware team and work in Olpe or Dortmund.

The job in bullet points  
  • Further development and maintenance of the OX App Suite application server
  • Identify functions that can be moved/refactored to dedicated services 
  • Extending the platform by Java-based microservices to build a standardized architecture
  • Development of new functionalities in Java as well as adding new components according to the OSGi model
  • Compiling of database queries for relational databases (SQL, MySQL)
  • Ensuring high quality through code reviews, pair programming and integration tests
  • Refactoring of our code in compliance with programming conventions
  • Collaboration in an agile team

Your background 
  • Completed studies with a focus on computer science
  • You know Java, object-oriented programming and basic design patterns.
  • You have experience in web programming, especially on the server side (Servlet API, Java Concurrency).
  • Relational databases (SQL) and Unix/Linux operating systems don't scare you
  • Working with a versioning tool is known to you (Git)
  • Good knowledge of both - German and English

We would be delighted about additional knowledge like
  • Ideally you already have knowledge of Eclipse, SOA and OSGi 
  • Experience with container platforms and container orchestration, namely Docker and Kubernetes
  • Knowledge of NoSQL, e.g. Cassandra
  • Understanding of the Gradle Build Tool & Jenkins
  • Familiarity with Gitlab

Our offer to you 
  • Working on a modern cloud software in an international team
  • Wide scope to develop your own ideas and projects
  • Flexible working hours and the ability to work from home
  • The most current and jazzy equipment
  • A culture of open and frequent feedback
  • Hackathons, Workshops and Team events
  • Continuous personal development & training
  • Language courses (e.g. German, English)
  • Company sports - entry to various gyms and swimming pools
  • A company pension scheme 
  • Flat hierarchies combined with an "Open Door" policy

Who we are
We are a hidden champion. When it comes to open source communication, office productivity and DNS-based security software and services, we are one of the leading players out there. Our 250+ employees around the globe are the reason, why our key products – the OX App Suite, Dovecot, and PowerDNS – are used by more than 200 million people for their private and business communications via partners such as Deutsche Telekom, GoDaddy, Strato, Orange, Comcast, or
For further questions, please contact Kerstin Florath via