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.
You will be involved in a variety of cutting-edge technical solutions, ranging from the latest .NET technologies using C# to various Front End Web JS Frameworks, all while contributing to our AI-powered platform evolution. You will be supported in your career growth by a highly experienced team, comprehensive learning opportunities, and a vibrant technical community committed to creating exceptional solutions that make a real difference in how our customers operate and succeed.
Role Purpose
As a Senior Software Engineer, you will 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 will work hands-on with cutting-edge UI frameworks, .NET Core backends, and cloud-native technologies while contributing to architectural decisions and ensuring high-quality software delivery across containerised, scalable web products.
Key Responsibilities
Technical Delivery
Design and deliver complex, scalable systems (multi-service integrations, high-traffic APIs, data processing pipelines) that anticipate edge cases, scalability issues, and long-term maintainability
Own large features or entire components across their complete lifecycle from conception to production support
Lead technical discussions and influence architecture decisions within team systems and components, with authority over component-level technical choices and escalation path to Engineering Lead for cross-team impacts
Drive technical excellence by establishing architectural patterns, standards, and best practice that others can follow
Ensure knowledge transfer and documentation for owned systems to enable team continuity
Collaboration & Communication
Lead story refinement sessions with Product Owners, providing technical expertise for estimation and risk assessment
Partner with cross-functional teams (product, design, QA) to deliver comprehensive solutions that meet business objectives
Influence technology choices based on deep technical understanding and business context
Lead team Agile ceremony facilitation to drive continuous process improvements, and establish team practices that enhance delivery predictability
Proactively identify and inspire resolution of technical debt and system improvements
Quality & Standards
Champion comprehensive quality practices including TDD/BDD standards, automated testing strategies, and shift-left testing
Lead security implementation across complex features establish security practices and conduct comprehensive security reviews
Establish development tooling and practices used consistently within the team
Lead troubleshooting efforts for complex software issues and production incidents
Establish documentation standards for complex team systems and drive knowledge transfer practices across team deliverables
Growth & Development
Mentor junior and mid-level engineers actively to raise team capability and technical standards
Lead team code review standards establishment conduct complex feature reviews, and drive quality improvements across team deliverables
Drive continuous improvement and champion responsible AI adoption with team governance practices
Required Experience & Skills
Technical Skills
Frontend Development: Strong proficiency with modern UI frameworks (e.g. Angular, React, Vue.js, Blazor) including performance optimisation and component architecture OR working knowledge with focus on backend specialisation
Backend Development: Strong proficiency with .NET Core, C#, ASP.NET Core Web APIs, REST, application architectures, and distributed systems
Database Systems and Data Architecture: Strong knowledge of SQL, NoSQL and data architecture decisions.
AI-Assisted Software Engineering: Experience with integrating AI tools (Cursor, Copilot, Devin, Claude Code, etc.) in engineering practices to accelerate design, development, testing and debugging. Using them critically and responsibly to improve quality, productivity and decision-making.
Observability: Advanced DataDog, Application Insights or Amazon CloudWatch implementation with performance tuning and cost optimisation
Infrastructure as Code: Infrastructure as Code with either Terraform, Bicep, ARM Templates or AWS CloudFormation/CDK
CI/CD Design: Design comprehensive CI/CD architectures for team deliverables, establish deployment strategies, and optimise pipeline performance for team efficiency
Cloud Architecture: Strong proficiency in SaaS using Azure (Functions, Queue, Blob[NN1] Storage, VMs, etc) or AWS (Lambda, SQS/SNS, EC2, etc.) services, infrastructure design, and performance tuning
Container Orchestration: Strong containerisation (e.g. Docker) or Kubernetes (AKS/EKS) experience with production-scale deployments
Architecture Expertise: Expertise in clean architecture principles, SOLID design patterns, and domain-driven design
Quality & Testing: Drive TDD/BDD adoption in team testing strategy and quality governance, and implement comprehensive automated testing with continuous improvement
Scalable Solutions: Experience with highly scalable solutions and internet-facing traffic levels
Performance & Scalability: Profiling and benchmarking applications.
Application Security: Confident vulnerability management, thread modelling and tracking
Production Support: Knowledge of observability and production support practices. Proficient in debugging complex issues, performance optimization, and production troubleshooting
Experience Requirements
5-7 years of professional software development experience
Proven ability in delivering complex, multi-system solutions
Experience working with highly scalable, internet-facing solutions serving millions of users
Demonstrated technical leadership through architecture decisions, technical mentoring, and cross-team collaboration
Track record of driving technical excellence, establishing standards, and influencing technology choices
Active mentoring experience with junior and mid-level engineers
Experience leading technical initiatives that span multiple sprints or quarters
Soft Skills
Strong analysis and problem-solving skills for troubleshooting technical issues
Excellent verbal and written communication skills with ability to explain technical concepts to non-technical stakeholders
Technical leadership and influencing skills without formal authority
Ability to utilise technical skills to develop and coach others through mentoring and knowledge sharing
Collaborative approach and ability to work as part of wider Engineering and QA teams
Conflict resolution skills for technical disagreements and cross-team coordination
Learning mindset with ability to adapt to new industry trends
Desirable Skills
Experience working with regulated or complex domains (finance, health, govtech) with audit requirements
Experience designing high-quality AI interactions through effective prompt engineering, efficient token usage, and optimisation techniques, combined with practical use of the Model Context Protocol (MCP) to integrate AI systems with tools and services for richer, automated workflows
Expertise with advanced monitoring and APM strategies using DataDog, including custom dashboards and alerting
Expertise with modern UI architecture patterns (micro-frontends, SSR/SSG)
Knowledge of security best practices and compliance requirements (OAuth2, OIDC, RBAC)
Experience with event-driven architectures
Experience in GraphQL APIs and real-time communication (SignalR, WebSockets)
Exposure to DevOps processes and automation ensuring end-to-end responsibility of features
Advanced cloud certifications in Azure or AWS
Impact: Your work will influence millions globally.
Growth: Continuous learning and career development opportunities.
Belonging: A culture that celebrates diversity and empowers every individual.
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.
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.