Principal Software Engineer AI Platform Modernisation

Stelfox Tech Recruitment; Cork; Hybrid; EUR 120,000 - 150,000; Full time

Job summary

Stelfox Tech Recruitment is partnering with a Cork-based Fintech provider to modernise their product and platform, embracing AI-first development to enhance Agentic AI services across their offerings deployed to US financial institutions.

We are seeking a Principal Software Engineer / Tech Lead to own the hardest problems—decomposing legacy systems, building modern replacements, and guiding incremental transition with a strong emphasis on code quality, tests, and scalable APIs.

Qualifications

• Expert-level experience with .NET/C# and modern patterns such as async/await, DI and clean architecture.
• Cloud-native development on Azure; AWS/GCP transferable.
• Database design, optimization, and migration for high-volume systems.
• CI/CD pipelines and automated deployment practices.

Responsibilities

• Lead the modernisation by decomposing legacy monolithic patterns into services.
• Raise the technical bar with coding standards, testing practices and engineering patterns.
• Bridge Legacy & Modern by aligning production systems with enterprise requirements.
• Leverage AI to accelerate modernization and unlock new product capabilities.

Skills

NET/C#

Azure

Database design

CI/CD pipelines

API design

Testing strategies

Refactoring

Job description

Stelfox Tech Recruitment is partnering with a Cork-based Fintech provider to modernise their product and platform, embracing AI-first development to enhance Agentic AI services across their offerings deployed to US financial institutions.

We are seeking a Principal Software Engineer / Tech Lead to own the hardest problems—decomposing legacy systems, building modern replacements, and guiding incremental transition with a strong emphasis on code quality, tests, and scalable APIs.