Salary: £21,000 - 42,000 per year Requirements: Must hold current SC Clearance Experience developing software across front-end and back-end (.NET APIs) Strong problem-solving skills and the ability to design solutions to business needs A security-first mindset with experience embedding controls into designs Comfortable working in Agile teams and collaborating with a range of stakeholders Experience with CI/CD, live service support, and modern engineering practices Responsibilities: Building and maintaining user-facing applications and back-end .NET API services Designing and developing secure, well-structured code using modern engineering standards Collaborating with user researchers to deliver user-centred solutions Supporting junior developers through mentoring and guidance Managing releases via CI/CD pipelines and supporting systems in production Technologies: API CI/CD Support REST Security ASP.NET More: We are Hays, looking for an SC Cleared Software Developer for one of our local clients in Cardiff. We offer a competitive rate of £600 per day inside IR35, with 1-2 days onsite and the rest working from home. You will join an Agile delivery team, working to build and support secure, high-quality software services for both internal and external users. last updated 17 week of 2026