Senior Software Engineer

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.

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.

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

Internal:
Engineering Teams, Engineering Lead/Manager, Accountancy Product Management, QA, Dev Ops, Architecture. External:
Professional Services, Customer Support, third‑party integration vendors.

• 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/No
  
  SQL 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 Cloud Formation/CDK) and containerisation (Docker/Kubernetes) at production scale

• Observability (Data Dog, App Insights, or Cloud Watch) 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

• 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

• 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