You develop and take ownership of a central billing system (C# / .NET, backend) and ensure its stable operation.
You work within an established .NET system landscape and take responsibility for the further development of a long-standing codebase.
You analyze complex business and technical contexts and make well-founded technical decisions that sustainably improve and purposefully modernize the system.
You identify technical debt early, assess it realistically, and drive pragmatic, effective modernization.
Within the team you communicate technical topics clearly, stand by your decisions, and provide guidance even in demanding situations.
You work with relational databases, web applications and REST APIs in the .NET environment.
You perform deployments, keep an eye on production operations, and follow issues through to a reliable solution.

You have at least 5–10 years of experience as a software developer with C# and .NET and are comfortable working in large, existing backend systems.
Object-oriented software development, ASP.NET, Entity Framework, REST APIs and relational databases are part of your core skill set.
You are willing to work primarily in mature .NET codebases (e.g. .NET Framework 4.7/4.8) and actively, realistically drive their modernization.
Clean Code, maintainable architectures and automated tests form the basis for your technical decisions.
You take responsibility, communicate clearly and can confidently represent technical positions.
Experience with CI/CD or AI-assisted development tools is a plus.
You have fluent German language skills (C1) and very good English skills (B2), both written and spoken.
Experience from product-oriented environments such as FinTech, platforms or SaaS is an advantage.

Company pension plan and 30 days of annual leave per year (based on a 5-day week)
Experienced colleagues who will support and welcome you to the team
The opportunity to shape our shared future – with a high degree of freedom and scope for implementation
The chance to make an impact across the Hypoport Group and to leverage support from the group
Trust as one of our company values, which we aim to live up to every day
A personal and flexible working environment where your needs are taken into account
An attractive workplace with regular after-work and team events and the option to bring dogs to the office
Daily free and fresh: lunch, drinks, brainfood as well as fruit and vegetables

Senior Software Developer, C# / .NET – Billing System

Key skills