Software Developer Backend (mf/d) Java/Kotlin, Spring Boot

United States Digital Space LLC; Darmstadt; Hybrid; EUR 55.000 - 85.000; Vollzeit

Benefits dieser Stelle

Hybrid work

30 days vacation

Gym membership subsidy

Job bike

Zusammenfassung

United States Digital Space LLC in Darmstadt invites a Backend Software Developer to join our energy and sustainability platform etaONE®. You will own backend services, implement REST APIs with Java or Kotlin, and help scale the system.

Collaborate with Product Owners, Frontend Developers, Data Scientists, and other stakeholders. You will write clean code, run automated tests, and continuously improve performance, reliability, and maintainability.

Qualifikationen

• At least 2 years of backend development experience.
• Strong knowledge of Java or Kotlin and Spring/Spring Boot.
• Experience designing and integrating REST APIs.
• Experience with PostgreSQL and data modeling.
• Automated testing, Git, code reviews, and clean code practices.
• Fluent English; German knowledge is a plus.

Aufgaben

• Develop and enhance backend services and REST APIs for etaONE platform using Java, Kotlin, and Spring Boot.
• Take ownership of complex features from concept through production-ready implementation.
• Collaborate with Product Owners, Frontend Developers, Data Scientists, and other stakeholders to translate requirements into robust solutions.
• Ensure high software quality through automated testing, code reviews, and clean code principles.
• Analyze and improve existing services focusing on maintainability, performance, and scalability.
• Share knowledge with the team and support less experienced colleagues.

Kenntnisse

Java

Kotlin

Spring Boot

REST APIs

PostgreSQL

Automated testing

Git

English (Fluent)

German (Nice to have)

Jobbeschreibung

Do you want to build software that makes a measurable impact on energy efficiency and sustainability?

At the company, we develop AI-powered energy management solutions that help industrial companies reduce energy consumption, CO₂ emissions, and operating costs. As a Backend Software Developer, you will take ownership of backend services and features for our etaONE® platform.

You will contribute your ideas to technical decisions, and continuously improve the scalability, maintainability, and quality of our software. At the same time, you will have room to grow your technical expertise and responsibilities.

Tasks

Develop and enhance backend services and REST APIs for our etaONE® platform using Java, Kotlin, and Spring Boot.

• Take ownership of more complex features, from technical concept through to production-ready implementation.
• Work closely with Product Owners, Frontend Developers, Data Scientists, and other stakeholders to translate requirements into robust technical solutions.
• Ensure high software quality through automated testing, code reviews, and clean code principles.
• Analyze and improve existing services with a focus on maintainability, performance, and scalability.
• Approach debugging and root-cause analysis in a structured way and help the team implement sustainable solutions.
• Share your knowledge with the team and support less experienced colleagues with technical questions.

Requirements

You bring a minimum of 2 years of hands-on experience in backend development

• Strong knowledge of Java or Kotlin and practical experience with Spring or Spring Boot
• You are confident in designing, developing, and integrating REST APIs.
• Experience with relational databases such as PostgreSQL allows you to independently develop data models and database queries.
• Automated testing, Git, code reviews, and clean code principles are part of your professional development workflow.
• You structure complex technical tasks independently and develop pragmatic, maintainable solutions.
• Use our AI tools to drive and improve your development.
• Fluent English skills enable you to work confidently in our international environment, German Knowledge is 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