Job description
Principal Software Engineer / Technical Lead - C#
Cork, Ireland (3 days in office)
A growing fintech engineering team is building a modern financial planning and analytics platform used by financial institutions to manage forecasting, performance analysis, and regulatory reporting.
The Cork-based engineering group is responsible for the product end-to-end and is currently undertaking a significant technical evolution — modernizing legacy architecture, introducing cloud-native practices, and integrating AI-powered development workflows to improve both engineering productivity and product capability.
This role is suited to an experienced Principal Engineer who thrives as a hands-on technical leader.
You will take ownership of some of the most complex engineering challenges involved in modernizing an established production platform while maintaining stability for customers.
The successful candidate will spend the majority of their time writing production code, solving difficult architectural problems, and mentoring engineers through example.
You will help guide the transition from legacy architecture to modern patterns through incremental, carefully executed changes that deliver continuous improvements without disrupting the existing platform.
What You'll Be Responsible For
- Driving Platform Modernization
- Lead the technical transformation of an established financial software platform. Break down legacy architectural patterns into modular, maintainable services and define practical migration paths that allow modern components to coexist with existing systems.
Hands-On Engineering
- Remain deeply involved in development, contributing production-quality code on a daily basis. Lead complex implementations, conduct detailed code reviews, and collaborate closely with engineers to solve difficult technical problems.
Raising Engineering Standards
- Establish strong development practices across the team including coding standards, testing approaches, and design patterns. Lead architecture discussions and design reviews that elevate the technical capabilities of the entire engineering organization.
Delivering Incremental Improvements
- Ensure modernization happens progressively rather than through disruptive rewrites. Each technical improvement should deliver measurable benefits such as improved performance, better testability, enhanced developer experience, or increased platform scalability.
Managing Legacy-to-Modern Transitions
- Work within the realities of an existing production system. Develop strategies that allow legacy components and modern services to coexist while gradually shifting the architecture toward more maintainable patterns.
Exploring AI-Enabled Development
- Leverage modern AI-assisted development tools to increase engineering efficiency and accelerate modernization work. Identify opportunities where AI capabilities could unlock new product functionality or improve development workflows.
Mentoring Engineers
- Support the growth of engineers across the team through code reviews, technical discussions, and collaborative problem solving. Promote a culture of engineering excellence and pride in craftsmanship.
Professional Background
- 10+ years of experience in software engineering with continued hands-on development
- Proven experience modernizing large-scale production systems
- Strong history of solving complex engineering challenges within teams of 15+ engineers
- Experience mentoring engineers and raising technical standards across a team
- Background in financial services or regulated industries is beneficial but not required
Technical Expertise
- Expert-level experience with .NET / C#, including modern architectural practices and performance optimization
- Strong full-stack development experience, including TypeScript and Angular
- Cloud-native application development experience (Azure preferred, though other cloud platforms are transferable)
- Database design, optimization, and migration strategies for high-volume systems
- Designing scalable APIs and managing versioning and backward compatibility
- Experience implementing testing strategies across unit, integration, and end-to-end testing layers
- CI/CD pipelines and automated deployment practices
- Large-scale refactoring and modernization approaches such as incremental decomposition or strangler patterns
AI and Modern Engineering Practices
This team actively incorporates AI-assisted development into day-to-day workflows (Claude Code, Cursor etc). Candidates should already be comfortable using AI coding tools to improve development speed, assist with problem solving, and enhance productivity.
If this sounds like you above and you want to join a company who are heavily embracing agentic AI moving forward as they modernise their entire product & engineering ecosystem, then this could be the position for you!
Feel free to apply for immediate consideration.
Please note:
We have a number of similar positions currently, and in the future, which we would like to discuss with you should you indicate your interest in this role. When we receive your application for this role, we will contact you to advise you of our process for other similar positions.
Stelfox is fully compliant with GDPR regulations and you can read more in our privacy policy here: https://www.stelfox.com/privacy-policy-gdpr/
Your shared data will not be disclosed or transferred to a third party data controller or data processor located outside the EEA unless we have obtained your express consent.
We look forward to working with you.
