menten GmbH in Bergisch Gladbach, near Cologne, is hiring a Java Developer (m/f/d) for its EDI software i-effect® and custom client projects. You will help move the code from Java 8 to Java 17, with 30 vacation days from year one, 2 to 4 home office days and flexible hours.
About menten GmbH
Product: i-effect®, EDI software for EDIFACT, ZUGFeRD and XRechnung
Work: Custom software for clients, from requirement to go-live
Modernisation: Porting i-effect® from IBM i to Ubuntu and from Java 8 to Java 17
Way of Working: One fixed Social Day a week for meetings, other days for focused coding
Benefits & Career Opportunity
Time Off: 30 vacation days from the first year
Work Model: 2 to 4 home office days and flexible hours, Mac or Windows
Money: Special payments in profitable years, with salary banding by experience
Extras: 30 euros a month for Urban Sports Club, Corporate Benefits with 800+ partners, parking or Jobticket
Position Overview
As Java Developer, you develop i-effect® further, and your code goes into live use. You help migrate the product from IBM i to Ubuntu and from Java 8 to Java 17. You design and build custom software for clients from requirement to go-live, in direct contact with users, and you help shape architecture decisions and interface design. The team uses AI tools such as Claude Code actively.
Why This Role Matters: You work on a real product and on client projects from start to finish, with a say in architecture whether you have three or ten years of experience. Home office, 30 vacation days and training budgets for conferences and certifications make it a sound choice for a developer who wants impact.
Key Responsibilities
Product Development
- Develop the EDI software i-effect® for EDIFACT, ZUGFeRD and XRechnung, with code that goes into production
- Help port i-effect® from IBM i to Ubuntu and raise the code base from Java 8 to Java 17
Client Projects
- Design and build custom software from requirement to go-live, in direct contact with users
Architecture
- Help shape architecture decisions and interface design
Qualifications & Requirements
Experience
- IT training or degree with 2 years of practical experience, or 3+ years of Java development
- Fluent German, and English for documentation
Skills
- Java and Spring Boot, REST interfaces, SQL (e.g. PostgreSQL), Git and CI/CD, agile working and AI coding tools
- Takes features all the way into production
- Clear communication with product owners and teams
Nice to Have
- IBM Power i/AS400, EDIFACT, ZUGFeRD, XRechnung
- TDD (JUnit, Mockito) and Docker
About menten GmbH
menten GmbH builds the EDI software i-effect® and custom software for its clients. The posting describes flat hierarchies, regular team events and Social Days, and a mix of a weekly meeting day and quiet days for coding.
How to Apply: Apply through HeyJobs. The posting lists no email or phone number. Salary is set within a band by experience and qualification, with no figure given.
Who Should Apply?
- Java Developers: Wanting product ownership
- Spring Boot Engineers: Interested in EDI and e-invoicing
- Legacy Migration Developers: With IBM i or AS400 knowledge
- Full-Cycle Developers: Who like client contact
- Cologne Region Talent: Wanting home office and 30 vacation days
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