Backend Developer

About The Company KEOZ GmbH is a software solutions partner and a subsidiary of S-Markt & Mehrwert GmbH & Co. KG. We bring together the stability of an established organization and the curiosity and energy of an innovative software company. At KEOZ, great software is built through trust, collaboration, and shared growth. Our teams work openly and respectfully, creating tailored digital solutions that deliver meaningful value.

Innovation, agility, and continuous development shape how we work. We value diverse perspectives, practical problem-solving, and a supportive environment where people can contribute ideas and grow professionally. Our goal is to build reliable, future-oriented solutions together—and to take pride in the results.

About The Role KEOZ GmbH is seeking a Backend Developer (m/f/d) to help develop and evolve modern backend services within a microservice architecture. In this role, you will turn requirements into scalable, maintainable software, with a strong focus on quality and performance. You will contribute throughout the development process, from planning and implementation to testing, documentation, and ongoing improvement.

You will work closely with colleagues in a collaborative team that values clear communication, sound engineering practices, and continuous learning. This is a permanent position with an annual salary range of €60,000 to €85,000, depending on experience and qualifications. The working model is hybrid, and you should be able to work from the office twice a week.

Qualifications

• Strong professional experience in backend development with Node.js.
• Experience with Fastify or a comparable HTTP framework.
• Confident use of TypeORM or a similar object-relational mapping tool.
• Experience with dependency injection; familiarity with Awilix is an advantage.
• Practical experience with test-driven development (TDD), preferably using Tap.
• Several years of experience building scalable backend services in a microservice architecture.
• Experience with relational databases such as PostgreSQL or MySQL.
• Good understanding of clean code and software design principles.
• Familiarity with agile and traditional development methods.
• A strong commitment to software quality, performance, and maintainability, together with a proactive and collaborative approach.
• Very good written and spoken German, at native or bilingual level.

Responsibilities

• Develop and enhance modern, scalable backend services within our microservice architecture.
• Implement product and technical requirements with attention to quality, performance, and long-term maintainability.
• Plan, implement, and automate test scenarios, applying test-driven development where appropriate.
• Work with the team using suitable agile or traditional development methods.
• Document code, architecture, workflows, and relevant technical decisions clearly.
• Investigate, diagnose, and resolve software defects and service issues.
• Identify opportunities to improve development processes and strengthen the technical foundation through appropriate modern technologies.
• Share knowledge and contribute to a constructive team culture built on openness, trust, and mutual respect.

Benefits KEOZ offers a permanent position, a competitive salary of €60,000–€85,000, and flexible working hours in a hybrid model. You will receive high-quality technical equipment, an ergonomic, modern workplace, and 30 days of annual leave. We support individual development through tailored learning and training opportunities, and encourage employees to bring forward ideas and help shape how we work. Additional benefits include regular in-house physiotherapy sessions, company events and team activities, and supplementary offers such as occupational pension provision or a public transport ticket. Employees can also make use of a business bike, on-site parking, and convenient access by public transport. Fresh fruit, sweet and savoury snacks, soft drinks, and coffee are available at the office.

Equal Opportunity

KEOZ GmbH is committed to a respectful, inclusive workplace where people can contribute and develop. We value diversity and welcome applicants from different backgrounds and experiences. We assess applications fairly based on relevant skills, experience, and potential, and aim to provide an environment where colleagues can work together openly and confidently.