Principal Software Engineer_Fullstack

**About Us** Sophos is a cybersecurity leader defending 600,000 organizations globally with an AI-driven platform and expert-led services. Sophos meets organizations wherever they are in their security maturity and grows with them to defeat cyberattacks. Its solutions combine machine learning, automation, and real-time threat intelligence with frontline human expertise from Sophos X-Ops to deliver advanced, 24/7 threat monitoring, detection, and response. Sophos offers industry-leading managed detection and response (MDR) alongside a comprehensive portfolio of cybersecurity technologies — including endpoint, network, email, and cloud security, extended detection and response (XDR), identity threat detection and response (ITDR), and next-gen SIEM. Together with expert advisory services, these capabilities help organizations proactively reduce risk and respond faster, with the visibility and scalability needed to stay ahead of evolving threats. Sophos goes to market with a global partner ecosystem, including Managed Service Providers (MSPs), Managed Security Service Providers (MSSPs), resellers and distributors, marketplace integrations, and cyber risk partners, giving organizations the flexibility to choose trusted relationships when securing their business. Sophos is headquartered in Oxford, U.K. More information is available at [](https://www.sophos.com). ### Role Summary We are looking for a Principal Software Engineer to provide hands-on technical leadership for the Central Platform Group. You will lead the architecture, design, and delivery of customer-facing capabilities spanning user interfaces, backend services, APIs, and shared cloud platforms. You will also help build secure, reliable AI experiences that connect customers with assistants and agents across Sophos products. This is a senior individual-contributor role with responsibility for production code, cross-team architecture, engineering quality, and technical direction. AI-driven engineering is a core expectation for this role. You will use AI coding agents as part of day-to-day software development and help establish effective agentic workflows that improve delivery speed and quality while preserving security, human review, and engineering accountability. **Team Summary** The Central Platform Group builds the shared customer-facing capabilities at the heart of Sophos Central and Sophos Fusion. This includes web experiences, backend services, APIs, identity and access capabilities, platform integrations, and AI-powered interactions used across the Sophos portfolio. ### What you will do - Lead the architecture, design, and delivery of end-to-end customer-facing features across web UI, backend services, APIs, and integrations. - Write production code, build prototypes, review designs and code, and remain directly involved in solving the most complex engineering problems. - Evolve shared frontend and backend platform capabilities so product teams can deliver consistent, accessible, and maintainable customer experiences. - Define clear service boundaries, APIs, data contracts, integration patterns, and versioning strategies for capabilities used across multiple Sophos products. - Design cloud-native, multi-tenant systems for security, scalability, availability, performance, resilience, and cost efficiency. - Apply secure-by-design principles to authentication, authorization, role-based access, tenant isolation, privacy, auditability, and customer-data handling. - Build a consistent and secure experience for customers to discover and interact with AI assistants and agents across Sophos products. - Develop reusable AI platform capabilities for request routing, context management, tool integration, orchestration, access control, and human oversight. - Establish practical approaches for AI evaluation, guardrails, regression testing, observability, latency, cost management, and safe failure behavior. - Use AI coding agents throughout the software development lifecycle for codebase exploration, design, implementation, refactoring, test generation, debugging, code review, and documentation; rigorously validate agent-generated changes before release. - Establish repeatable agentic development practices for task decomposition, context management, human review, automated verification, and the safe use of coding agents across engineering teams. - Translate product goals and ambiguous technical problems into architectural direction and incremental delivery plans. - Mentor engineers, raise engineering standards, and build alignment across product, UX, security, applied AI, and platform teams. ### What you will bring - 12+ years of software development experience, currently operating at Principal, Staff, Architect, or equivalent level. - Hands-on experience building production AI applications or agentic workflows - not only prototypes. - Strong proficiency using AI coding agents across design, implementation, testing, debugging, code review, and documentation. - Strong architecture and system-design experience for large-scale, customer-facing SaaS products. - Hands-on backend development with Go and/or Java and frontend development with Angular and/or React. - Experience designing, deploying, and operating secure microservices and APIs on AWS. - Demonstrated technical leadership, including driving design decisions, solving complex production problems, and mentoring engineers. - Cybersecurity domain experience is desirable but not mandatory.