Principal Engineer

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

Job summary

Stelfox Tech Recruitment partners with a Fintech provider in Cork City undergoing a product and platform modernisation. You will work on legacy .NET systems, migrating towards modern architecture with AI-assisted development support.

We seek expert-level .NET/C# developers with Azure cloud experience, SQL Server, API design, testing, and strong CI/CD practices to deliver scalable solutions in a hybrid Cork-based role.

Qualifications

• Expert-level experience with .NET / C#, deep understanding of async/await, DI, clean architecture and domain modeling.
• Cloud-native development on Azure (AWS/GCP transferable).
• Database design, optimization and migration strategies for high-volume systems.

Responsibilities

• Contribute to a platform modernisation by building parallel solutions alongside live systems.
• Design scalable, versioned APIs with backward compatibility and robust testing.
• Deliver CI/CD pipelines and automate deployments to production.

Skills

.NET / C#

Async/await

Dependency Injection

Clean Architecture

Domain Modeling

Azure Cloud

SQL Server

CI/CD

API Design

Testing Strategies

Tools

Azure DevOps

Git

Visual Studio

SQL Profiler

Entity Framework

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).
• 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.