Product Software Engineer (Back End Java) (M/W/D) in Köln

• WE ARE LOOKING FOR YOU AS
• PRODUCT SOFTWARE ENGINEER (BACK END JAVA) (M/W/D)
• LIMITED IN COLOGNE

Interzero is one of the leading service providers in closing product, material, and logistics cycles and a pioneer in plastics recycling, operating Europe’s largest sorting capacity.

Guided by the principle of “zero waste solutions,” the company supports more than 80,000 customers across Europe in the responsible handling of recyclable materials, helping them improve their sustainability performance and conserve primary resources.

With around 2,000 employees, Interzero generates annual revenues of nearly one billion euros.

According to Fraunhofer UMSICHT, Interzero’s recycling activities alone saved approximately 1.04 million tons of greenhouse gas emissions and 8.09 million tons of primary raw materials compared to primary production in 2024. Further information at:

www. interzero. de .

What is it about?

• Collaboration: Together with Product, UX and Front-End colleagues, design and implement the Java back ends of both brand-new and evolving products you’ll stay with for the long haul.
• Modeling: Translate business goals into sturdy domain models and reliable services that deliver real customer value.
• Architecture: We’re moving toward a headless, microservice-oriented landscape.

As a senior, you’ll help create clean APIs, refine coding standards and champion the right refactorings.

• Automation: Build and refine Git Lab pipelines, Docker images and workflow engines that remove manual steps - both in development and inside the products themselves.
• Frontend partnership: Partner closely with front-end teams so the data, endpoints and performance they need are always there, making the user experience shine.
• Leadership: Mentor junior engineers, run architecture sessions or even lead a small squad when it fits your personal goals.
• Innovation: Experiment with new Java features, cloud services and patterns that help us close product loops faster. Your ideas are welcome.

Advantages

• Job Security: You can expect a varied, exciting, and secure role with one of the largest environmental service providers in a future-proof industry.
• Compensation: You receive performance-based pay with a strong focus on maintaining your work-life balance.
• Flexibility: You benefit from flexible working hours and the option to work remotely.
• Creative Freedom: You work in an environment where ideas, initiative, and creative freedom are encouraged and supported.
• Flat Hierarchies: You operate within flat hierarchies and quickly take on responsibility for your own tasks.
• Collaboration: You experience a culture of collaboration and respect at eye level, both within and beyond your team.
• Development: You have access to internal and external training and development opportunities.
• Health: You benefit from a comprehensive health management program.
• Benefits: You receive attractive perks such as corporate benefits, bike leasing, free drinks and fruit on-site, and coverage of the Germany ticket or an Edenred card.

Profile

• Experience: 5 + years of professional Java experience, ideally with Spring Boot and Hibernate/JPA.
• Expertise: Deep knowledge of RESTful API design, relational databases (My SQL/Postgre SQL), and containerization with Docker.
• Frontend-Familiarity: Familiarity with our frontend technology stack (React/Next. js/Type Script) can be advantageous; if you want to work full-stack, you can.
• Dev

Ops: Familiarity with Git Lab CI/CD — our Dev Ops team handles the heavy lifting, but you know your way around.

• Architectural Judgment: A sense for clean architectures, test automation, and the judgement to choose the right pattern at the right time.
• Languages: Fluent English (German is a bonus), a collaborative mindset and genuine curiosity about how products succeed in the real world.
• EU-Work: A valid EU work permit; candidates already based in Germany (or nearby EU countries) are strongly preferred.

Contact

Yannick Bartsch hr@interzero. de