Staff .NET Developer / Principal Engineer - Cloud & Platform ArchitectureAt a GlancePrincipal / Staff-level engineering role leading a full platform transformationDeep .NET / C# stack with modern cloud-native architecture (Azure / AWS)Hybrid working - Belfast city centre officeReal ownership over technical direction, this role has teethAbout the CompanyOur client is a technology organisation on a genuine platform transformation journey, moving away from complex legacy systems toward a modern, cloud-native architecture. Operating at significant scale, they work with multiple engineering teams across Belfast and international sites, and are investing heavily in raising their engineering bar technically and culturally. If you want to make a visible, lasting impact on a mission-critical platform, this is where you do it.The RoleThis is a senior leadership position combining architectural ownership with people leadership. Reporting into the CTO / Head of Engineering, you'll define the long-term technical direction, guide teams through a significant legacy modernisation programme, and work closely with senior stakeholders to ensure every architecture decision supports both product ambition and future scale. This isn't advisory you'll own the outcomes. The right person is someone who thrives with genuine autonomy and wants to lead change, not just recommend it.Key ResponsibilitiesArchitecture & Platform ModernisationDefine and own the target architecture, leading the transition from legacy systems to modern, cloud-native platformsDrive the decomposition of monolithic systems into modular services, APIs, and event-driven componentsIntroduce modern engineering practices and tooling to improve delivery quality, reliability, and developer experienceCollaborate with frontend and backend leaders to ensure scalability, performance, and consistency across the platformTechnical LeadershipProvide architectural oversight across multiple teams and applicationsLead platform evolution initiatives including cloud migration, containerisation, and CI/CD automationChampion software craftsmanship, testing strategies, and design patternsIdentify and resolve complex technical and performance issues across distributed systemsEngineering Management & CultureLead and mentor engineering managers and senior engineers across Belfast and international sitesEstablish and run architecture governance through review boards and technical working groupsSupport team growth, performance, and long-term capability developmentHelp scale engineering culture and processes as the organisation growsDelivery & Stakeholder EngagementOwn the delivery of strategic technical initiatives from design through to implementationWork with product, infrastructure, and senior leadership to define architectural roadmapsCommunicate architectural decisions clearly to both technical and non-technical audiencesDevelop proofs of concept and technical spikes using modern languages and frameworksWhat You'll NeedEssential10+ years' professional software engineering experienceStrong .NET / C# background across legacy and modern frameworksProven track record leading large-scale platform modernisation programmesExperience operating at Principal Engineer, Architect, Engineering Manager, or equivalent levelDeep understanding of distributed systems, APIs, and event-driven architecturesHands-on experience with Azure or AWS and container platforms such as KubernetesExperience leading and mentoring multiple engineering teamsAbility to communicate complex technical concepts at senior leadership levelRight to work in the UKNice to HaveExperience with architectural experimentation and prototypingBackground working across Belfast-based and international engineering teamsFamiliarity with SQL Server, PostgreSQL, and performance optimisation at scaleWhy Apply?Lead a major platform transformation with long-term, visible impactReal ownership and genuine influence over technical direction - not a seat at the table, the head of itSupportive engineering culture built on quality, trust, and deliveryClear progression paths across Principal Engineer, Head of Engineering, and Enterprise ArchitectureWork alongside experienced engineers and leaders who care about doing things properlyHybrid working with a Belfast city centre officeInterested?Reach out to Ryan Quinn directly on LinkedIn for a confidential conversation, or submit your CV via the link below.We represent the largest selection of technology roles of any recruitment firm in Northern Ireland, if this one isn't the right fit, we're always happy to meet and talk through where you want to go in 2026. Skills:.Net AWS ReactBenefits:BonusWHJS1_NI