Senior .NET Developer (System Owner) - On Site, Castleford

You will be the primary technical owner of an established system, working directly with senior leadership to drive ongoing development, improvements and stability. The system is already live and heavily used, so your focus will be on understanding, maintaining and evolving an existing codebase rather than building something new from scratch.

We are also keen to explore how modern technologies, including AI, can be applied in practical ways to improve efficiency, automation and decision-making within the business.

The Role

• Take full technical ownership of an existing .NET-based system
• Work closely with the business to deliver new features, improvements and bug fixes
• Understand and improve a SQL-based database structure and performance
• Maintain and enhance a legacy codebase with minimal documentation
• Introduce structure where needed (version control, deployment processes, documentation)
• Identify opportunities to apply AI and automation to improve internal processes and system capability

We are looking for a highly capable, hands-on Senior .NET Developer to take ownership of a business-critical internal system used across Arrow Film and Foil Converters and Film and Foil Solutions Limited, part of a PLC group., * Strong experience with C# and .NET (Framework or .NET Core)

• Solid SQL Server experience (query writing, optimisation, database understanding)
• Proven experience working on and improving existing or legacy systems
• Ability to work independently and take ownership of technical decisions
• Comfortable operating as the sole developer within a business
• Strong problem-solving skills and a pragmatic approach

Desirable (but not essential)

• Experience using AI tools or integrating AI into business systems
• Interest in automation, optimisation and modern development approaches
• Experience improving internal systems rather than building products from scratch

Important

This role will suit someone who:

• Enjoys taking control of a system and making it their own
• Is comfortable working without perfect documentation
• Prefers real business impact over working in large development teams
• Can translate business requirements into practical technical solutions

• Direct impact on a growing business within a PLC group
• High level of ownership and autonomy
• Opportunity to shape and improve a system that is central to operations
• Ability to introduce modern technologies, including AI, where they add real value
• Work directly with decision-makers, not layers of management

This is an on-site role based in Castleford.

If you are looking for a role where you can take real ownership, solve meaningful problems and see the direct impact of your work, we would like to hear from you.

Job Type: Full-time

Pay: £60,000.00-£90,000.00 per year

Benefits:

• Company pension
• Discounted or free food
• Free parking
• Life insurance
• On-site parking