Senior AI Software Engineer - Modernisation & Parity Testing

Stelfox Limited; Dublin; On-site; EUR 90,000 - 130,000; Full time

Job summary

Stelfox Limited is partnering with a Dublin-based software company to hire a Senior AI Software Engineer (C++ or C#/.NET) on a contract basis. The role is fully remote across Ireland or the UK, with an initial 3-month term and strong potential for extension or permanent opportunities.

The successful candidate will lead the modernisation of legacy systems, design AI-assisted engineering workflows, and implement automated validation to ensure safe migration of functionality.

Qualifications

• Proven track record modernising legacy applications.
• Experience designing automated testing frameworks, regression testing, and test automation strategies.
• Experience with API-first architectures and API design.
• Experience with SQL Server and data-intensive applications.
• Strong understanding of software architecture and system design.

Responsibilities

• Design and build a parity testing framework to validate migrated functionality.
• Introduce automated testing and regression validation across a large legacy codebase.
• Lead the adoption of AI-assisted software development approaches and engineering workflows.
• Define standards, tooling, governance, and development conventions for agent-assisted engineering.
• Partner with engineering teams to modernise legacy functionality safely.
• Support transition towards an API-first architecture.
• Establish measurable engineering practices to improve delivery predictability and throughput.
• Ensure knowledge transfer so internal teams can own and evolve the approach long-term.

Skills

C++

C#

.NET

Legacy modernization

Automated testing

API design

SQL Server

System architecture

AI-assisted development

Job description

Stelfox Limited is partnering with a Dublin-based software company to hire a Senior AI Software Engineer (C++ or C#/.NET) on a contract basis. The role is fully remote across Ireland or the UK, with an initial 3-month term and strong potential for extension or permanent opportunities.

The successful candidate will lead the modernisation of legacy systems, design AI-assisted engineering workflows, and implement automated validation to ensure safe migration of functionality.