How to Hire a .NET Developer for Enterprise and Integration Work

The .NET Hiring Problem

.NET has been enterprise software's default stack for over two decades. That history means the talent pool is large and diverse, spanning everything from VB.NET developers maintaining 15-year-old Windows Forms apps to ASP.NET Core developers building microservices on Azure. When you post a .NET developer role, you attract both.

For enterprise and integration work, the distinction matters. Here is how to identify the right profile for serious .NET projects.

Modern .NET vs Legacy .NET

The transition from .NET Framework (Windows-only, runs on IIS) to .NET Core and now .NET 8+ (cross-platform, containerised, cloud-native) is the most significant shift in the ecosystem's history. A developer who has only worked on .NET Framework will need a learning curve on dependency injection, middleware pipelines, async/await patterns, and deployment to Azure App Service or containers.

Ask candidates specifically: have they worked on .NET 6+ projects, or primarily .NET Framework? The answer shapes everything else.

Skills That Define Senior .NET Work

Async and concurrent programming

Modern ASP.NET Core is built on async/await. Developers who block async code with .Result or .Wait() cause thread pool starvation under load. This is one of the most common performance problems in .NET APIs that look fine in development and fall over in production. A senior .NET developer understands the async/await state machine, knows when to use ConfigureAwait(false), and can diagnose deadlocks that only appear under concurrent load.

Entity Framework and raw SQL judgment

Entity Framework Core is the standard ORM for .NET. The trap is using it for everything, including queries where EF generates inefficient SQL that would be simple and fast as a raw query. Strong .NET developers know when EF is the right tool and when to drop down to Dapper or raw ADO.NET for performance-critical paths. They also understand migrations, change tracking, and the N+1 query problem.

Dependency injection and testability

.NET Core has first-class dependency injection built in. Developers who register everything as singletons, or who write code that cannot be unit tested because dependencies are created with new inside methods, are writing code that will be expensive to maintain. Look for developers whose code is structured around interfaces and who write tests that do not require a running database or HTTP server.

WCF and legacy integration experience

Enterprise .NET work regularly involves WCF services, SOAP APIs, and legacy systems that predate REST. Developers with only modern ASP.NET Core experience will struggle with WS-Security, WSDL parsing, MTOM encoding, and the patterns required to migrate or extend legacy services without breaking existing consumers. If your project involves legacy integration, ask specifically about WCF experience.

Azure Integration

.NET and Azure are a natural pairing. Senior .NET developers for enterprise work should be comfortable with Azure Service Bus for async messaging, Azure AD for authentication, Azure App Service and Container Apps for deployment, and Key Vault for secrets management. Azure-specific knowledge is increasingly required on enterprise .NET engagements even when the application logic is not cloud-specific.

Interview Questions

• What is the difference between Task.Run and async/await? When would you use each?
• Walk me through how you would migrate a WCF service to ASP.NET Core REST without breaking existing consumers.
• How do you handle database migrations in a zero-downtime deployment?
• How would you implement a background processing queue in ASP.NET Core?
• What is your approach to structuring a solution with multiple projects in .NET?

Red Flags

• Uses .Result or .Wait() on async methods
• No experience with the .NET dependency injection container
• Cannot explain the difference between .NET Framework and .NET Core / .NET 5+
• Has only worked on greenfield projects, no legacy system experience
• Cannot write a unit test for an ASP.NET Core controller

Our .NET Work

Our most significant .NET engagement was migrating the UN-DGACM's full-text document indexing system from WCF to ASP.NET Core REST with Azure Service Bus, achieving a 3x throughput improvement with zero downtime. We have also delivered .NET OAuth2 integrations for enterprise clients, WCF-to-REST migration services, and C# data pipeline work across healthcare and government sectors.

If you need a .NET developer who has handled enterprise migrations, Azure integrations, and legacy system work in production, get in touch.