Principal Software Engineer

Stelfox Tech Recruitment; Ireland; Hybrid; EUR 90,000 - 120,000; Full time

Job summary

Stelfox is partnering with a Fintech provider in Cork City undergoing a product and platform modernization, embracing AI-assisted development to extend AI capabilities on top of their enterprise product line.

You will feel comfortable around legacy .Net platforms and have lived through a migration or platform modernisation initiative by building a parallel solution alongside an existing live system running in production.

Qualifications

• Expert-level experience with .NET / C#, deep understanding of frameworks, modern patterns (async/await, dependency injection, clean architecture, domain modeling).
• Strong full-stack development experience, including TypeScript/Angular
• Cloud-native development on Azure (AWS/GCP are transferable)
• Database design, optimization, and migration strategies for high-volume systems
• CI/CD pipelines and automated deployment practices
• Designing scalable APIs and managing versioning and backward compatibility
• Experience implementing testing strategies across unit, integration, and end-to-end testing layers
• Large-scale refactoring and modernization approaches such as incremental decomposition or strangler patterns

Responsibilities

• Contribute to product & platform modernization leveraging AI-assisted development.
• Work on legacy .NET platforms and migration initiatives by building parallel solutions alongside live systems in production.
• Collaborate with cross-functional teams to deliver scalable APIs and robust testing strategies.
• Lead design reviews and guidance on clean architecture and domain modeling.

Skills

.NET / C#

TypeScript/Angular

Azure cloud

Database design & tuning

CI/CD

API design & versioning

Testing strategies

Legacy modernization

Tools

SQL Server

Azure DevOps

Job description

Stelfox is partnering with a Fintech provider located in Cork City who are going through a product & platform modernisation process as they truly embrace the power of AI-assisted development to help extend AI capability on top of their existing product line for their enterprise customers.

You will feel comfortable around legacy .Net platforms and have lived through a migration or platform modernisation initiative by building a parallel solution alongside an existing live system running in production.

Topics that you are use to:

• .Net Internals - how thread pool and async/await interact
• SQL Server - performance optimisation, running profiler, indexing, partitioning, utilising Azure SQL elastic pool and look maybe look at moving logic into the APIs.
• Working inside the IDE and pushing code to production daily and utilising AI code assistants or agent platforms to your advantage (Cursor, Claude code etc).

Experience & Skills requirement:

• Expert-level experience with .NET / C#, deep understanding of frameworks, modern patterns (async/await, dependency injection, clean architecture, domain modeling).
• Strong full-stack development experience, including TypeScript/Angular
• Cloud-native development on Azure (AWS/GCP are transferable)
• Database design, optimization, and migration strategies for high-volume systems
• CI/CD pipelines and automated deployment practices
• Designing scalable APIs and managing versioning and backward compatibility
• Experience implementing testing strategies across unit, integration, and end-to-end testing layers
• Large-scale refactoring and modernization approaches such as incremental decomposition or strangler patterns

Please note, this position is located in Cork with 3 days in office, 2 remote from home, so candidates will need to be either located in or near Cork or be willing to relocate for this opportunity.