Senior Developer - C#

Senior Developer – C#/.NET UK based | Flexible remote working with occasional London office meetings | Competitive salary and benefits I'm working with a growing cybersecurity business looking for a Senior Developer to help shape the next generation of its products. This is a hands-on role with genuine influence over architecture, technical standards and how software performs in production. You'll work across a shared C#/.NET stack covering two areas: a cloud platform built around Azure and microservices, and a file processing engine with command-line tools and libraries. You don't need to be an expert in both, but you should bring real depth in one and be keen to work across the wider product. What you'll be doing

• Designing and building reliable, high-performance software in C# and .NET.
• Taking ownership of technical decisions, code quality and production reliability.
• Modernising existing systems and solving complex technical problems.
• Mentoring developers and helping the team make effective use of testing, automation and AI development tools.
• Working closely with product, QA and support teams to deliver improvements that matter to customers. What we're looking for You'll have strong commercial C#/.NET experience, sound architectural judgement and a track record of delivering complex production software. You'll also be comfortable working with Linux, CI/CD and automated testing. Experience in either Azure-based distributed systems or engine, CLI and library development will be particularly relevant. Exposure to Docker, Kubernetes, messaging, file processing or native interop would be useful, depending on your background. This is a senior technical position rather than a line management role, making it a strong opportunity if you enjoy building software while guiding others. The package includes flexible working, 25 days' holiday plus public holidays, private medical insurance, pension and protection benefits. Interested? Get in touch for a confidential conversation.