Principal Software Engineer

Sepura Limited; Waterbeach; On-site; GBP 90,000 - 120,000; Full time

Job summary

Sepura Limited is seeking a Principal Software Engineer to lead the architecture and performance of critical public safety systems. You will mentor teams, drive best practices, and shape the development lifecycle across C#/.NET platforms.

The role emphasizes low-latency, highly available solutions, with a hybrid work model (two days at home, three days in the office) and opportunities to influence product strategy.

Qualifications

• Degree in a relevant discipline required.
• 10+ years of professional software development experience with C#/.NET.
• Deep experience designing scalable, distributed systems (microservices).
• Experience with Web Applications development.
• Knowledge of protocols and technologies common in high-availability systems (TCP/IP, gRPC, messaging).
• Expertise in performance tuning, concurrency, and low-latency processing.
• Strong security understanding for critical infrastructure.
• Excellent problem-solving, communication and leadership skills.
• UI front-end frameworks such as WPF, MVVM, MVP or MVC.

Responsibilities

• Lead architecture, design, and implementation of high-performance, secure systems in C#/.NET.
• Develop low-latency applications handling high-volume data traffic.
• Set technical vision and strategy for the platform in line with business goals.
• Conduct code reviews, establish standards, and drive CI/CD pipelines.
• Troubleshoot complex issues ensuring maximum uptime and reliability.
• Mentor mid-level and senior developers and promote technical excellence.

Skills

C#/.NET

Distributed systems

Web Applications

UI frameworks (WPF/MVVM/MVP/MVC)

Leadership / mentoring

CI/CD & DevOps

Security principles

Performance tuning

Networking protocols (TCP/IP, gRPC)

Education

Degree in a relevant discipline

Tools

Docker

Kafka

RabbitMQ

gRPC

Job description

We are looking for a Principal Software Engineer to join the team. This role is central to ensuring the reliability, performance, and scalability of systems vital for public safety and essential services. You will act as a technical leader, mentoring other engineers and driving best practices across the development lifecycle.

Key Responsibilities

• Lead 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. The Software Team follows an Agile development process centred around Scrum ceremonies. During each sprint you may take on several tasks related to several of the responsibilities listed above. After 3 months in the role, the successful candidate could work two days from home and three days in the office, with the requirement to be in the office on an ad‑hoc basis when required.

What you need to succeed

Must-haves:

• Degree in a relevant discipline.
• 10+ years of professional software development experience, with significant focus on C# and the .NET framework (including .NET Core/.NET 5+).
• Deep expertise in designing and developing highly scalable, distributed systems (e.g., microservices architecture).
• Experience with development of Web Applications.
• 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.
• Experience using virtual environments such as Docker.
• Experience using Kotlin/Java.
• Toolchain configuring (CI/CD, version control, defect tracking tools, code analysis, automated testing).