Senior .NET Developer - Remote (Northern Ireland) About our client Our client is a leading technology provider delivering scalable, secure, and high-performing solutions to enterprise customers. They are now seeking a Senior .NET Developer to join their remote Northern Ireland team, working on mission-critical applications that impact customers across multiple sectors. This role offers the chance to work on complex systems, leverage modern cloud technologies, and contribute to a collaborative engineering culture. Job Summary As a Senior .NET Developer, you will design, develop, and maintain enterprise-grade applications, frameworks, and workflows. You will work across the full software development lifecycle, from architecture and design to testing and deployment. The role demands hands-on coding experience, a strong focus on quality and testing, and the ability to collaborate with cross-functional teams to deliver scalable, secure, and maintainable solutions. Key Responsibilities Architect and develop applications, workflows, and prototypes to meet business needs. Refactor and extend existing codebases to fix defects and add functionality. Build enterprise-grade frameworks for engineers, prioritising security, scalability, and configurability. Develop complete test plans, including unit, integration, and end-to-end tests, ensuring high code coverage. Resolve defects throughout QA, pre-production, production, and post-release cycles. Refine functional requirements and produce detailed technical specifications. Generate clear technical documentation to communicate architectural and design decisions. Communicate and collaborate across teams, stakeholders, and external partners to drive engineering efforts. Essential Skills & Experience 5-7 years' hands-on experience with C#/.NET development. Strong experience with Azure/cloud technologies and/or relevant accreditations. Proven experience building secure, standards-compliant applications and APIs (REST, SOAP, XML/JSON). Solid understanding of design patterns, multi-tenant SaaS architectures, and enterprise-grade systems. Strong TDD mindset and experience writing extensive automated tests. Experience with NoSQL databases (Cassandra, Cosmos DB, or similar) and relational databases (SQL Server, Oracle). Familiarity with message queue systems (RabbitMQ, Kafka, MSMQ, Event Hub). Experience with .NET Core, microservices, and distributed systems. Exposure to Agile methodologies (Scrum, Extreme Programming) and tools such as Git, Jira, and Confluence. Ability to work in a fast-paced environment delivering iterative, mission-critical projects. Desirable Skills Experience across multiple platforms/languages (Java, Microsoft stack, Open Source technologies). Familiarity with cloud-first design and serverless architectures. Strong problem-solving, analytical, and collaboration skills. Education Bachelor's degree in Computer Science, Software Engineering, or a related field (Master's preferred). Why Join? Fully remote working across Northern Ireland. Competitive salary up to £50k, depending on experience. Opportunity to work on mission-critical, enterprise-grade applications. Collaborative, supportive culture with mentoring and career growth opportunities. Exposure to cutting-edge cloud and distributed system technologies.