Senior Software Engineer (US)

About IRIS IRIS Software Group is one of the UK's largest privately held software companies, trusted by 100,000+ businesses, schools and accountancy firms to keep their operations running. Our software pays 1 in 6 UK employees, supports over 12,000 schools, and is relied on by 91 of the top 100 UK accountancy firms. We're a Great Place to Work® certified employer, recognised for our commitment to well-being, inclusion and development - and we're growing fast. 1. Role Specification Role As a Senior Software Engineer, you'll be a technical leader within your team, responsible for delivering complex full-stack web applications, serving millions of users, driving technical excellence, and mentoring other engineers. You'll work hands-on with cutting-edge UI frameworks, .NET Core backends, and cloud-native technologies while contributing to architectural decisions and ensuring high-quality delivery across containerised, scalable products. You'll join our Document Management team within the Accountancy product line, building systems for managing and securely retrieving client documents that CPA and accounting firms rely on daily - working remote or hybrid from our Salt Lake City office alongside a close-knit engineering team. Main Responsibilities Technical Delivery Design and deliver complex, scalable systems - document processing, storage, and workflow systems - that anticipate edge cases and long-term maintainability Own large features or components end-to-end, from conception through production support Lead technical discussions and influence architecture decisions within owned systems, escalating cross-team impacts to the Engineering Lead Establish architectural patterns and standards others can follow Collaboration & Quality Lead story refinement with Product, providing technical input for estimation and risk Champion TDD/BDD, automated testing, and security reviews - with particular rigour on document integrity and data security Lead troubleshooting for complex issues and production incidents Proactively identify and drive resolution of technical debt Growth & Development Mentor junior and mid-level engineers, raising team capability and technical standards Lead code review standards and conduct complex feature reviews Champion responsible AI adoption within team practices Key Relationships Internal: Engineering Teams, Engineering Lead/Manager, Accountancy Product Management, QA, DevOps, Architecture. External: Professional Services, Customer Support, third-party integration vendors. 2. Qualifications & Experience Technical Skills Strong .NET Core, C#, ASP.NET Core Web APIs, REST, and distributed systems; strong or working proficiency in a modern UI framework (Angular, React, Vue.js, Blazor) Strong SQL/NoSQL and data architecture skills Cloud architecture on Azure (Functions, Queue, Blob Storage, VMs) or AWS (Lambda, SQS/SNS, EC2), with Infrastructure as Code (Terraform, Bicep, or CloudFormation/CDK) and containerisation (Docker/Kubernetes) at production scale Observability (DataDog, App Insights, or CloudWatch) with performance tuning and cost optimisation Clean architecture, SOLID, and domain-driven design principles TDD/BDD-driven testing strategy, profiling/benchmarking, and production troubleshooting at internet-facing scale Application security: vulnerability management and threat modelling Practical use of AI coding tools (Copilot, Claude Code, etc.) in day-to-day engineering Experience Requirements 5–7 years of professional software development experience Proven delivery of complex, multi-system solutions at internet-facing scale, serving millions of users Demonstrated technical leadership through architecture decisions and active mentoring, without formal authority Track record leading technical initiatives spanning multiple sprints or quarters, establishing standards and influencing technology choices Desirable Experience with content or document management systems, ideally within accounting or professional services Experience with e-signature or workflow integrations, and event-driven architectures Knowledge of security/compliance standards (OAuth2, OIDC, RBAC); experience in regulated or audit-heavy domains 3. Competencies Strong analysis and problem-solving for complex technical issues Communicates technical concepts clearly to technical and non-technical stakeholders Leads and influences without formal authority; coaches through mentoring Collaborative, with sound judgement in technical disagreements Learning mindset, adaptable to new tools and industry trends 4. Additional Information Benefits Competitive salary, private medical healthcare, life assurance and pension, generous holiday allowance, senior technical leadership development, conference and community engagement opportunities, and flexible/hybrid working. IRIS is Great Place to Work certified and a Best Workplace for Women. This role will evolve with the needs of the business. IRIS and IRIS Software & Services are trademarks. © IRIS Software Group 2026. Why You’ll Love Working Here Impact: Your work will influence millions globally. Growth: Continuous learning and career development opportunities. Belonging: A culture that celebrates diversity and empowers every individual. Ready to Apply? Click Apply - we’re excited to learn about your unique perspective and experience. If you need adjustments during the process, let us know. We’re committed to making this opportunity accessible to everyone. What to expect from our hiring process Our process is designed to be fair, transparent and straightforward. Stages vary depending on the role — more senior positions may involve additional steps, and some areas include role-specific assessments such as a technical test or case study — but typically you can expect: Application review — we assess your experience and potential Initial call — a short conversation to learn about you and share more about the role Skills assessment — tailored to the position, e.g. case study, coding challenge or portfolio review Final interview — meet the team and explore how you'll make an IMPACT at IRIS We'll always walk you through the specific stages at the start of the process so you can prepare with confidence. If you need any adjustments or accommodations during the process, let us know, we’re committed to making this experience accessible for everyone.