Senior Software Developer (m/f/d)

In the world of IT commerce, we go new ways: the largest assortment, personal advice and profound solution competence – from a single source. We work with over 300 employees throughout Germany and with one of the largest online shops in Germany. Our comprehensive manufacturer portfolio and our bundled specialist expertise ensure that we can always provide the right solution for individual requirements. Since its founding in 1990, JACOB has come far: Over the decades, we have developed from a regional store business in Karlsruhe to an important IT service provider for companies. Our firm will to constantly seek innovative approaches has enabled this development. And this creativity, coupled with expertise, we take part in the future. We want to further develop and maintain what we do. Are you going this way with us?

We are looking for: As Senior Software Developer (m/w/d), you will be able to shape the technical orientation of our systems and take co-responsibility for how we grow as an engineering team – professionally and culturally.

You are responsible for architectural decisions for our internal tools and backend systems and accompany their entire life cycle – from conception to realization to operation You actively drive our transformation towards modern, scalable software architecture, and you are questioning existing structures where it makes sense You develop backend services in C# and/or Go, focusing on clean code, automated testing and continuous improvement You take technical leadership: You write RFCs and ADRs, evaluate make-or-buy decisions and introduce your own impulses into the technical roadmap You accompany younger colleagues: both as a Sparring partner and mentor and thus maintain the development quality throughout the team You agree closely with partner teams and bring your expertise in cross-disciplinary decisions

What distinguishes you as a personality:

You have a strong will to design - you want to build systems not only but to improve them sustainably You clearly represent technical positions, but remain open to better arguments See mentoring as a natural part of your role and enjoy sharing knowledge You actively question processes and architectures, not to criticize, but to find real solutions You use AI-assisted development tools strategically: you evaluate their use, establish best practices in the team and use them as a multiplier for collective development speed Legacy Code is not a reason to complain, but the starting point for sound improvements

What skills you should bring: completed study of computer science, mathematics or a comparable technical training At least 5 years of experience in software development with C# and/or Go, of which at least 2 years in a leading technical role Knowledge of software architecture and the development of cashier, manageable systems Detectable experience with architectural decisions (e.g. RFCs, ADRs) and their communication in the team Safe handling of relational databases (MySQL, MSSQL) and experience in database modeling Sovereign, reflective use of modern development assistants (e.g. Claude Code, Codex)- from conception via boiler plate and documentary to automated test suites Experience with container-based development (e.g. Docker) Solid experience with Docker and Kubernetes Cluster Safe handling of CI/CD pipelines, including deployment workflows in Kubernetes environments Knowledge in xUnit.net, Camunda, BPMN, AWS and Terraform are advantageous Flowing German knowledge (min. B2) and good English knowledge in word and writing

This is our current Tech Stack: Languages & Frameworks: C#, Go, .NET, Entity Framework Infrastructure & Cloud: AWS, Terraform, Docker, Kubernetes, ArgoCD Databases: MSSQL, Postgres, MySQL Integration & Messaging: RabbitMQ, REST APIs Processor design: Camunda, BPMN Tooling & Quality: GitLab, Jira, xUnit.net Legacy: WinForms

At JACOB you will find a modern working environment that offers you free space for your own ideas and new challenges. This means:

You benefit from our Benefits: Employee discount on our huge product range, JobRad, Occupational Care, Workplace Goggles, Free Beverages and Ticket Restaurant Clear that you receive modern IT equipment to work We offer a hybrid model for mobile work Design options and space for ideas Our People Development helps you develop yourself in your role and personality The DU belongs to us: From the beginning - during the interview to the exchange with the management Cold water? You will be prepared and worked intensively into your varied and exciting task by your colleague At JACOB, the focus is on man. The most diverse experiences and characters are represented in our development teams – and we are looking for even more! Diversity plays an important role for us. .