Senior Software Developer (m/f/d) Java/Kotlin with Spring Boot

United States Digital Space LLC; Darmstadt; Vor Ort; EUR 70.000 - 110.000; Vollzeit

Benefits dieser Stelle

Hybrid work

30 days vacation

Gym membership

Job bike

Team events

Zusammenfassung

United States Digital Space LLC in Darmstadt is seeking a Senior Software Developer to lead backend development on the etaONE platform. You’ll own technical direction, shape architecture, and help grow the engineering team with your experience.

You will design scalable REST APIs with Spring Boot (Java/Kotlin), work in a cloud-native microservice stack, and advocate for clean code, testing, and modern DevOps practices including Docker, Kubernetes, and CI/CD.

Qualifikationen

• At least 5 years of backend software development with Spring Boot or comparable frameworks.
• Strong proficiency in Java and/or Kotlin.
• Experience building RESTful APIs and working with SQL databases (PostgreSQL).
• Deep understanding of software architecture and clean code principles.
• Experience with CI/CD pipelines and automated testing.
• Experience taking technical ownership and mentoring others.

Aufgaben

• Design, develop, and maintain scalable backend features from REST APIs to the persistence layer using Spring Boot with Java and/or Kotlin.
• Contribute to cloud-native microservice architecture and its evolution.
• Improve system landscape with Docker, Kubernetes, CI/CD pipelines, and asynchronous pub/sub mechanisms.
• Provide technical input for new product ideas, including architecture and technology decisions.
• Ensure high code quality through test-driven development and automated testing (JUnit, Mockito, MockK) and code analysis.
• Mentor and support junior developers while promoting learning and knowledge sharing.
• Collaborate with product management and domain experts to translate requirements into scalable solutions.
• Stay up-to-date with backend, cloud, and software engineering trends.

Kenntnisse

Spring Boot

Java

Kotlin

REST APIs

SQL

PostgreSQL

Software architecture

CI/CD

JUnit/Mockito/MockK

Mentoring

English

Tools

Docker

Kubernetes

CI/CD tooling

Jobbeschreibung

Do you want to build software that truly makes an impact? At the company, we develop intelligent energy management solutions that help industrial companies reduce energy consumption, lower CO₂ emissions, and cut costs. With our AI- and data-driven products, we actively contribute to a more sustainable future.

As a Senior Software Developer, you will join our backend team in Darmstadt and work on our etaONE® platform. You will take technical ownership, actively contribute to architectural decisions, and support the growth of our engineering team with your experience. If you care about clean code, modern architectures, and meaningful software, you will feel right at home with us.

Tasks:

• Design, develop, and maintain scalable backend features – from REST APIs to the persistence layer – using Spring Boot with Java and/or Kotlin
• Actively contribute to the evolution of our cloud-native microservice architecture
• Continuously improve our system landscape using modern technologies such as Docker, Kubernetes, CI/CD pipelines, and asynchronous pub/sub mechanisms
• Provide technical and functional input for new product and solution ideas, including architecture and technology decisions
• Ensure high code quality and long-term maintainability through test-driven development, automated testing (e.g., JUnit, Mockito, MockK), and static code analysis
• Mentor and support junior developers while fostering a strong engineering culture focused on learning and knowledge sharing
• Collaborate closely with product management, developers, and domain experts to translate business requirements into scalable technical solutions
• Actively participate in internal knowledge exchange and continuously stay up to date with backend, cloud, and software engineering trends

Must-have:

• At least 5 years of professional experience in backend software development with Spring Boot or comparable frameworks
• Strong proficiency in Java and/or Kotlin
• Experience in building RESTful APIs as well as working with SQL and data modeling
• Hands-on experience with relational databases, ideally PostgreSQL
• Solid understanding of software architecture, clean code principles, and modern software engineering practices
• Experience with CI/CD pipelines and automated testing (e.g., JUnit, Mockito, MockK)
• Experience in taking technical ownership, mentoring, or supporting less experienced developers
• Fluent English skills, both written and spoken

Nice-to-have:

• Hands-on experience with Docker and container-based architectures
• Experience with Kubernetes and cloud-native platforms
• Experience with asynchronous architectures or event-driven systems
• German language skills are a plus

Benefits:

• Purpose-driven work: Support industrial companies in becoming more efficient and sustainable
• Flexibility: Hybrid working with home office options and flexible working hours
• Team spirit: A supportive, collaborative environment with plenty of room for exchange and cooperation
• Community: Regular team events and shared activities
• Work-life balance: 30 days of vacation plus a flexible, agile work culture
• Well-being: Tax-free benefits card, subsidized local gym membership and the option of a job bike