Developer C# / .NET as Freelancer (all genders)

Vexcash AG; Berlin; On-site; EUR 96,000 - 165,000; Full time

Job summary

VEXCASH AG in Berlin is seeking an experienced Developer C# / .NET to join as a Freelancer and contribute to the development of modern, reliable, scalable web applications in FinTech. You will design and build robust backend services, APIs and data-driven applications using .NET 8+ and ASP.NET Core, ensuring high code quality, performance, security and maintainability.

English is required; German is a plus.

Qualifications

• Strong professional experience with C# and the .NET ecosystem.
• Hands-on experience with .NET Framework maintenance of legacy apps.
• Proven experience designing and building RESTful APIs.

Responsibilities

• Develop clean, maintainable C# code based on requirements.
• Design, develop and maintain backend apps using .NET 8+, ASP.NET Core, EF Core.
• Design and implement RESTful APIs following best practices.
• Work with SQL Server including data modelling and performance tuning.
• Use EF Core and ADO.NET for data access and persistence.
• Implement automated unit and integration tests.
• Apply architecture principles and design patterns.
• Collaborate using Git-based workflows and code reviews.
• Contribute to CI/CD pipelines and automated deployments.
• Work with Azure services and cloud-based architectures.
• Analyze, troubleshoot and resolve technical issues.
• Contribute to ongoing code quality and development processes.
• English required; German a plus.

Skills

C# language

English proficiency

German language a plus

Agile development

Problem solving

Communication

Tools

Git

Azure

CI/CD

SQL Server

ADO.NET

RESTful APIs

Entity Framework Core

ASP.NET Core

Job description

About Vexcash AG

VEXCASH AG is Germany’s leading online provider of short-term loans. We offer our customers a quick and straightforward solution to bridge the gap until their next payday. More than 800,000 customers already rely on our service. Thanks to our innovative approach, they can secure financial liquidity without having to commit to a long-term agreement.

We are looking for an experienced Developer C# / .NET to join our team and contribute to the development of modern, reliable, and scalable web applications in the FinTech sector as Freelancer.

You will work in a skilled and collaborative environment using modern Microsoft technologies, primarily .NET 8+ and ASP.NET Core. Your main focus will be on designing and developing robust backend services, APIs, and data-driven applications while ensuring high standards of code quality, performance, security, and maintainability.

Your responsibilities

• Develop clean, maintainable, testable, and reusable C# code based on business requirements and user stories

• Design, develop, and maintain backend applications and services using .NET 8+, ASP.NET Core, and Entity Framework Core

• Design and implement RESTful APIs following best practices and scalable architecture principles

• Work with SQL Server, including data modelling, query optimization, and performance tuning

• Work with Entity Framework Core and ADO.NET for efficient data access and persistence

• Implement automated unit and integration tests to ensure software quality and reliability

• Apply software architecture principles, design patterns, and clean code practices

• Collaborate using Git-based workflows and participate in code reviews

• Contribute to CI/CD pipelines and automated deployments

• Work with Microsoft Azure services and cloud-based architectures

• Analyze, troubleshoot, and resolve technical, functional, and performance issues

• Contribute to the continuous improvement of code quality, architecture, scalability, and development processes

What you bring

• Strong professional experience with C# and the .NET ecosystem

• Hands-on experience with .NET Framework, including maintenance and enhancement of legacy applications

• Strong experience with .NET 8+ and ASP.NET Core for modern backend development

• Solid experience with Entity Framework Core and ADO.NET

• Proven experience designing and building RESTful APIs

• Strong knowledge of SQL Server, relational database design, and query optimization

• Good understanding of software architecture principles, design patterns, and clean code

• Experience with automated testing frameworks such as xUnit, NUnit, or MSTest

• Experience using Git in collaborative development environments

• Familiarity with CI/CD pipelines and automated deployment processes

• Experience with Microsoft Azure and cloud-based application architectures

• Experience working in agile development environments

• Strong analytical and problem-solving skills with a strong focus on code quality

• Good command of English, German is a plus