Senior .NET Developer (C#), Energy Sector

 Location: Hybrid, South West London / Surrey border

 Salary: £80,000–£85,000 + bonus and benefits

 Type: Permanent

A growing, independent energy data specialist is looking for a Senior .NET Developer to join its Agile delivery team. You’ll build and evolve secure, high-volume transaction systems that support the UK energy market, part of the country’s critical national infrastructure.

This is a hands-on senior role. You’ll design and deliver complex features, shape engineering standards, and mentor others while staying close to the code.

What you’ll be doing

• Designing and building complex features in modern .NET (C#)
• Turning business and regulatory requirements into robust technical solutions
• Working with Product Owners on refinement, estimation and sprint planning
• Leading technical investigations and resolving complex production issues
• Reviewing code for maintainability, performance and security
• Contributing to CI/CD pipelines and release automation
• Supporting secure integrations using certificate-based authentication

What we’re looking for

• 5+ years’ commercial experience with .NET and C#
• Strong experience building APIs, services and distributed systems
• Experience with certificate management and secure communications
• CI/CD, Git-based workflows and containerisation (e.g. Docker)
• Strong Agile experience, including refinement and estimation
• Excellent problem-solving and communication skills, with the confidence to mentor others

Highly desirable

• Energy or utilities sector experience
• AWS or Azure
• Event-driven or message-based architectures
• Regulated or high-assurance environments

Why apply?

 You’ll work on technically complex, real-world systems with genuine influence over architecture and engineering standards, in a collaborative, privately owned business that’s growing.