Fullstack Developer (Focus: Backend)

Do you love controlling complex systems in the background, but also want to contribute in other areas? We are looking for tech all-rounders who can master complex architectures and are motivated to participate in various fields. You understand how data needs to flow to perform perfectly across all platforms. As part of our crew, you use AI not just as a tool but as a turbo to blur the boundaries between disciplines and build pioneering software solutions.

Development of new APIs with Spring & Kotlin and design of database solutions with MongoDB

Orchestration of AI agents for automation of code generation and refactoring

Integration of LLM interfaces into scalable backend services

Architecture, unit testing, and clear documentation in Swagger

Continuous optimization of the developer experience through AI workflows

Close collaboration with the crew in the implementation of web or mobile features

Sparring with design and PM for technically sound and cross-platform solutions

Ensuring seamless performance across all platforms

In-depth knowledge of Kotlin, the Spring Framework, and MongoDB

Deep understanding of common patterns, API standards, and modern architectures

Confident use of AI coding tools such as Claude Code

Ambition to think beyond the backend and assume technical ownership

Ability to critically validate AI-generated architectures and logic

Communicative, team-oriented, and open to new tech stacks

Fluent in German or English

Know-how in web technologies (React/Next.js) or mobile (Swift/Kotlin Multiplatform)

Experience in integrating LLM interfaces into backend services

Experience with Docker and GitLab CI/CD pipelines

Experience with cloud infrastructure (AWS, DigitalOcean)

Proficient handling of API tools like Bruno or Postman

Your salary depends on your qualifications and experience. Based on your seniority, we offer a significant overpayment above the collective agreement minimum salary. Legal notice: The IT collective agreement (ST1) applies to this position. The minimum base salary according to the collective agreement for this position is € 3,954.00 gross per month (based on 14 times/year).