Java Backend Developer - Spring Boot & Camunda (m/f/d)

Who We Are

Rockstardevelopers, founded in 2015 in Mannheim, with additional offices in Stuttgart and Munich. We are a software development company with experience from hundreds of individual projects for enterprise and medium-sized customers.

Short paths, honest feedback, no political games. No hierarchy levels between you and the people who make decisions.

Your Tasks

You will work in customer projects for large companies and public clients, embedded in their teams, with full responsibility for your area.

• Conception, development, and testing of microservices in the Java environment
• API development: REST and SOAP, synchronous and asynchronous, specification with OpenAPI 3
• Process automation with Camunda BPM
• Test automation with JUnit 5 and Cucumber
• Operation of your own services: deployment, monitoring, error analysis
• Shaping architecture, not just implementing it
• Generating, reviewing, and refactoring code with Claude Code, Copilot, or Cursor
• Coordination with interface partners across team boundaries

Most people come to one of the offices one to two days a week. However, there is no compulsion to do so. You will only be on-site with the client for individual appointments every few weeks.

Honest upfront: On-call duty is part of the job

In some of these projects, you will also support the services you develop in operation - including scheduled on-call duty. This is regulated and shared within the team.

Where You'll Land

Depending on the project and your experience:

• Large corporations like Deutsche Bahn / DB Systel (rail-specific domains: timetable management, sales, control and signaling technology)
• Public sector / authorities (e.g., Federal Employment Agency, ITZBund, Federal Printing Office) – regulated environments, accessibility, security by design
• Enterprise and medium-sized customers from various industries

Experience in one of these environments is a strong plus – tell us where you come from in the questions.

What You Bring

Senior level. Our clients need people who deliver from day one and work independently.

Backend Core (what we expect):

• Java and Spring Boot, plus Spring Data and Hibernate/JPA
• Microservices: conception, development, testing
• REST and SOAP web services (JSON/XML over HTTP), OpenAPI 3
• PostgreSQL and Oracle
• JUnit 5 and Cucumber
• Docker and Kubernetes
• CI/CD with GitLab Pipelines, build with Maven
• Git, Jira, Confluence, agile working

What sets you apart:

• Camunda BPM from real projects, not from a tutorial
• OAuth 2.0 and Keycloak for authentication and authorization

Advantageous (not a must):

• Apache Kafka and asynchronous communication
• XML, XSD, XSLT
• Experience in complex projects with multiple participating teams
• J2EE legacy systems and their migration to Spring Boot

Language: German as a native language or at C1/C2 level, fluent English. You coordinate daily with business departments and interface partners.

You don't have to know everything. The Java core is important, and that you can quickly get up to speed with new stacks.

AI Tools Are Mandatory, Not a Bonus

Claude Code, Copilot, Cursor: You must be able to work productively with them. Not because we want to be hip, but because our clients expect it and that's how we work. If you consider AI tools a hype and prefer to type everything yourself: wrong company. Internally, we invest in your AI skills.

What We Offer

• Home office, office, or a mix, you decide
• MacBook (unless the client provides their own hardware)
• Various clients, various projects
• The founders are your direct contacts
• Internal upskilling in AI development

Application

CV is sufficient. No cover letter needed. After a short video Q&A round (2x90 seconds), we will get back to you within a few days.