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Jobs at Open-Xchange

Interested in becoming part of something big?
You have landed in the right place. We are always looking for great talent to join our variety of departments. Check out our current job vacancies below or send us your speculative application. Become part of an exciting team at OX.

Dortmund | Olpe | Europe | rdmi01

Java Middleware-Developer (f/m/d)

Don’t just go to work. Thrive. 
We need people who are committed to openness, have a rebellious business spirit and the will to revolutionize the market.

Open people for open source! 
By joining OX as part of a special team, this position is a launch pad for highly talented individuals to build their experience and access many opportunities working for OX globally. 

Our Vision
A borderless internet that is open, safe and free

We are eMail 
Worldwide companies like: Comcast, Cox, 1&1, STRATO, Deutsche Telekom, Vodafone, Orange, Unitymedia, ItaliaOnline, Host Europe, NetCologne, network solutions / and Rackspace all use our "white label" products for eMail and collaboration.


OX App Suite is one of the market-leading web applications in the e-mail environment that is used by millions of users every day. You help to develop the application server of this modern open source cloud software and expand its platform with additional microservices. You are part of the 14-strong middleware team and work in Olpe or Dortmund.


What do you have to do

  • Further development and maintenance of the OX App Suite application server
  • 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


That is what you offer

  • 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 containering, e.g. Docker
  • Knowledge of NoSQL, e.g. Cassandra
  • Overview in NIO Programming in Java, e.g. Netty
  • Experience with Reactive Programming


That is what we offer

  • Exciting work on a modern open-source cloud software in an internationally operating company
  • Plenty of scope for your own ideas and design decisions
  • Flexible working hours and the ability to work from home
  • Equipped with the up-to-date hardware
  • Hackathons, workshops and team events
  • Trainings and continuous personal development
  • Flat hierarchies with an "Open Door" philosophy
  • Personal development in a dynamic environment
  • A company pension scheme
  • Company sports - Free entry to various gyms and swimming baths

About Open-Xchange

Open-Xchange (OX) is a market leader in Mail / Messaging and DNS-based security services, with more than 200m seats sold through international hosting and telco providers worldwide, including partners such as 1&1, Orange, Italiaonline, Comcast, GoDaddy or Softbank.

We at OX have our roots in Open Source, and this has shaped our view of the world and culture – open, diverse, and with a bias to act, giving everyone at OX room to take responsibility within their team and grow. OX believes in an internet that is open, safe and free. We want to create competitive products that allow our providers to deliver secure internet services with a great user experience, and that respect privacy and generate value.

With some 270+ people worldwide, OX develops and operates Open Source software (aaS) for mail / messaging (OX App SuiteOX Guard) and collaboration / productivity (OX DriveOX Documents). OX’s  Dovecot is the world’s dominant open-source IMAP server software, and our PowerDNS provides secure DNS services to our telco customers and their users.

Our business is fast-paced and changing constantly. We are looking for people who share our beliefs, who are out there to make a difference, are entrepreneurial and enjoy working in a high-tech environment as part of a truly international team. OX is headquartered in Cologne, with further locations throughout Germany (Hamburg, Bremen, Dortmund, Olpe and Nuremberg), the USA (Louisville, KY), Finland, the Netherlands, Italy, France, Spain and Japan (Tokyo).

If you are interested, please contact Jochen F. Schude for further information - or send us your paperless application with a cover letter including the job ID (see at the top left corner), tabular CV, certificates, salary expectations and the earliest possible date of entry by e-mail to recruiting at