C# Developer

Jefferson Frank; Oslo; On-site; NOK 900,000 - 1,100,000; Full time

Job summary

Jefferson Frank is seeking a Backend Software Engineer in Oslo to design, develop, and maintain scalable backend services built on .NET. You’ll work with C# and F# in a microservices and cloud-native environment, delivering RESTful APIs and distributed systems.

Ideal candidates will have strong C# experience, familiarity with ASP.NET Core and Entity Framework, and an interest in AI-assisted coding tools. Collaboration and problem solving are essential in this role.

Qualifications

• Strong commercial experience developing C# applications.

Responsibilities

• Design, develop, maintain, and enhance backend services built using C# and F#.

Skills

C# programming

REST API design

Microservices architecture

Distributed systems

Problem solving

Communication

Tools

ASP.NET Core

Entity Framework

F#

GitHub Copilot

Claude Code

Kubernetes

Azure

PostgreSQL

Job description

About the Role

We are looking for a talented Backend Software Engineer to join our engineering team and contribute to the development, enhancement, and maintenance of a modern platform built on .NET technologies. This role offers the opportunity to work on scalable backend services, microservice-based architectures, and cloud-native solutions while leveraging AI-assisted development tools to improve productivity and code quality.

You will primarily work with C# and .NET technologies, with exposure to F# within parts of the existing codebase. Candidates with hands-on F# experience are highly desirable, although developers keen to learn and work with F# are also encouraged to apply.

Key Responsibilities

• Design, develop, maintain, and enhance backend services built using C# and F#.
• Build and support scalable .NET applications and microservices.
• Develop and maintain RESTful APIs and message-driven services.
• Collaborate with cross-functional teams to deliver high-quality software solutions.
• Write clean, maintainable, and well-tested code following best practices.
• Troubleshoot, debug, and resolve production issues.
• Participate in code reviews and contribute to continuous improvement initiatives.
• Leverage AI-assisted development tools such as GitHub Copilot, Claude Code, and similar technologies to accelerate development and improve efficiency.
• Support the ongoing evolution of the platform architecture and technical standards.

Required Skills & Experience

• Strong commercial experience developing applications in C#.
• Experience with .NET Backend Development, including:
  • ASP.NET Core
  • Entity Framework (or similar ORM technologies)
• Experience working with REST APIs and service-based architectures.
• Understanding of microservices architecture and distributed systems.
• Experience with message-based communication systems.
• Exposure to F#, or a genuine interest in learning and working with it.
• Proficiency using modern AI-assisted coding tools such as GitHub Copilot, Claude Code, or similar.
• Strong problem-solving skills and attention to detail.
• Excellent communication and collaboration abilities.

Desirable Skills

• PostgreSQL
• Kafka
• Kubernetes
• Microsoft Azure
• Experience working in cloud-native or containerised environments.

What We're Looking For

We're seeking a proactive engineer who enjoys solving complex technical challenges, thrives in a collaborative environment, and is passionate about building reliable, scalable backend systems. You'll be comfortable working across an evolving technology stack and excited by the opportunity to help shape the future of the platform.