Full Stack Developer required, by our marketing leading client in South Wales. Our client sits within the defence industry so a level of security clearance would be required. Location: South Wales (Hybrid – 2 days a week onsite) An established defence-technology organisation is seeking a Full Stack Software Developer to join its growing engineering function. This role suits an individual with strong experience across modern Microsoft and JavaScript technologies, who enjoys building secure, resilient and scalable software used in critical environments. The successful applicant will contribute to the development of advanced digital solutions, working across the full lifecycle — from design and architecture through to deployment and continuous improvement. This position offers long-term career progression, a collaborative technical environment, and the chance to work on systems with national importance. Main Responsibilities: * Design and implement server-side components and services using C# and modern .NET frameworks * Build and enhance web applications using React and TypeScript * Develop and maintain robust APIs and distributed services * Work closely with cross-functional teams to deliver high-quality technical solutions * Participate in secure-by-design development practices and code reviews * Support CI/CD workflows and assist with performance optimisation * Provide guidance to junior team members where required Ideal Background: * 5 years’ commercial full stack development experience * Degree in Computer Science or similar discipline * Strong capability with C# / .NET (latest frameworks) and React with TypeScript * Hands-on experience with both relational and non-relational databases * Knowledge of API-centric architectures and distributed systems * Practical experience with version control and CI pipelines (e.g. Git-based platforms) * Strong analytical and debugging skills, with a collaborative mindset Desirable: * Any Cloud exposure * Knowledge of Docker * Event-driven architecture or messaging platforms This excellent position offers the opportunity to obtain security clearance, a competitive salary, and an outstanding benefits package, including an annual bonus, pension scheme, healthcare, 25 days’ annual leave plus Bank Holidays, and many additional perks