Senior Software Developer (Back-end)

The Role Are you a highly skilled full stack contractor looking to make an immediate impact on a modern, high-visibility platform? At ONYX Insight, we’re looking for a Senior Software Contractor to join our team, with a primary focus on backend delivery using C# .NET, alongside contributing to our React frontend services. This is a hands-on contract role where you’ll be trusted to hit the ground running, deliver high-quality code, and contribute to the evolution of our core platforms supporting the renewable energy sector. You’ll work closely with product, design, and engineering teams to build scalable, performant user interfaces, while also supporting backend integrations where needed.

Key Responsibilities

• Deliver High-Impact Backend Solutions: Own the development of responsive, high-performance applications using C# .NET (primary focus).
• Full-Stack Contribution: Support frontend development with React (secondary focus), ensuring seamless integration between frontend and services.
• Build & Ship Quickly: Work in an agile environment to design, develop, and release features efficiently with minimal oversight.
• Collaborate Effectively: Partner with cross-functional teams to translate requirements into practical, user-focused solutions.
• Drive Code Quality: Write clean, maintainable, and scalable code, following best practices across both frontend and backend.
• Support Delivery & DevOps: Contribute to CI/CD pipelines and deployment processes to ensure reliable and consistent releases.

Ideally, You’ll Have/be

• Strong commercial experience with C# .NET (5+ years preferred) – this is the core focus of the role
• Solid experience with modern frontend tooling (state management, component libraries, testing frameworks)
• Working knowledge of React (2+ years) to support frontend services
• Proven track record delivering software in contract or fast-paced environments
• Experience building scalable, performant web applications
• Familiarity with cloud platforms (AWS preferred)
• Experience with relational databases (PostgreSQL ideal)
• Comfortable working autonomously, managing priorities, and delivering to tight timelines
• Strong communication skills and a pragmatic, delivery-focused mindset.

About ONYX

ONYX Insight is a growing technology and engineering organisation in the renewable energy sector. Our vision is to build a more efficient future by becoming the world’s most innovative provider of predictive technology solutions. Our advanced sensing, software and analytics combined with our engineering experience are deployed on wind turbines around the world to maximise production and make turbines more reliable for longer, optimising energy production. ONYX Insight is part of the Macquarie Group. Macquarie is a global financial services group operating in 34 markets in asset management, leasing and asset financing, market access, commodity trading, renewables development, specialist advisory services, capital raising and principal investment. The diversity of the Macquarie Group operations combined with a strong capital position and robust risk management framework has contributed to a 54 year-record of unbroken profitability.

For any further information, or to understand our products and services better, please feel free to look through our website: https://onyxinsight.com/

ONYX Insight are an equal opportunity employer and value diversity at our company. We do not discriminate based on race, religion, colour, national origin, gender, sexual orientation, age, marital status, veteran status, or disability status.