Senior C# Developer

JobAdder Operations Pty; Waterbeach; Remote; GBP 90,000 - 130,000; Full time

Job summary

Sepura Ltd, based in Waterbeach, Cambridge, is seeking a Senior C# Developer to lead design, development and optimization of our mission-critical communication infrastructure. You will work with the Software team to evolve existing PC applications and future microservices architectures.

You will drive technical vision, implement resilient, low-latency systems, review code, set standards, and mentor mid-level and senior engineers.

Qualifications

• 5+ years of professional software development experience with C#/.NET.
• Experience designing scalable, distributed systems (microservices).
• Proficiency with TCP/IP, messaging services and high-availability patterns.
• Strong security principles for critical infrastructure.
• UI front-end experience with WPF/MVVM/MVP/MVC.
• Excellent problem-solving and leadership skills.

Responsibilities

• Architect, design, and implement high-performance, secure communication systems using C#/.NET.
• Develop low-latency applications handling high-volume data traffic.
• Drive technical vision and CI/CD adoption.
• Conduct code reviews and establish coding standards.
• Mentor mid-level and senior developers.

Skills

C#/.NET

Distributed systems design

Performance tuning

Security principles

Technical leadership

UI frameworks (WPF/MVVM)

Education

Degree in relevant discipline

Tools

Kafka

RabbitMQ

gRPC

CI/CD pipelines

WPF

Job description

This role is central to ensuring the reliability, performance, and scalability of systems vital for public safety and essential services.

22nd September, 2026

We are looking to recruit an experienced and highly skilled Senior C# Developer to lead the design, development, and optimisation of our mission-critical communication infrastructure. Working alongside other Software application team members, the candidate will be responsible for the development, integration and maintenance of the existing PC applications and our future microservices based architectures and APIs. Come and join Sepura Ltd at an exciting time of growth and progress your career within this innovative technology company, based in Waterbeach, Cambridge.

Role:

• Contribute to the architecture, design, and implementation of high-performance, resilient, and secure communication systems using C#/.NET.
• Develop robust, low-latency applications that handle high-volume data traffic (e.g., messaging queues, real-time data processing).
• Drive technical vision and strategy for the platform, ensuring alignment with long-term business goals and industry standards.
• Conduct code reviews, establish coding standards, and implement continuous integration/continuous delivery (CI/CD) pipelines.
• Troubleshoot and resolve the most complex technical issues, ensuring maximum system uptime and reliability.
• Mentor and guide mid-level and senior developers, fostering a culture of technical excellence and innovation.

Day to Day:

Our customer base includes many different industries and markets around the world. Our complete TETRA and LTE solutions have been developed specifically for users in multiple sectors to face their critical communications challenges. There is no such thing as a typical day here at Sepura. You will be supported by your manager and team, as well as collaborating with other departments across the business. The Software Team at Sepura follows an Agile development process centred around the heartbeat of Scrum ceremonies. During each sprint you could be taking on several tasks related to several of the responsibilities listed above.

What you need to succeed

Must-haves:

• Degree in relevant discipline

Experience and Skills:

• 5+ years of professional software development experience, with significant focus on C# and the .NET framework (including .NET Core/.NET ).
• Deep expertise in designing and developing highly scalable, distributed systems (e.g., microservices architecture).
• Proven experience with protocols and technologies common in communication or high-availability systems (e.g., TCP/IP, gRPC, messaging services like Kafka or RabbitMQ).
• Expertise in performance tuning, concurrency, and multithreading to achieve low-latency processing.
• Strong understanding of security principles related to critical infrastructure.
• Excellent problem-solving, communication, and technical leadership skills.
• UI front-end frameworks such as WPF, MVVM, MVP or MVC

Nice to have:

• Planning software projects (considering resourcing, task dependencies, tool requirements, etc)
• Working in an Agile SCRUM environment
• Java including application framework such as spring, hibernate
• Experience with Python or PowerShell scripting
• A working knowledge of legacy WinForms applications
• Toolchain configuring (CI/CD, Version Control, Defect tracking tools, code analysis, automated testing)