Microsoft ships two eras of .NET web development. .NET Framework (4.x) is Windows-only and mature but in maintenance. .NET / ASP.NET Core (6, 7, 8+) is cross-platform, open source, and where new features land.
When ASP.NET Core fits well
- New greenfield web apps, APIs, and microservices
- Linux/Docker/Kubernetes deployments and cloud-native Azure workloads
- Teams wanting unified SDK, modern C#, and long-term support (LTS) releases
When legacy .NET Framework might remain
- Large monoliths tied to System.Web, WebForms, or Windows-specific APIs
- Third-party libraries not yet ported to .NET Core
- Strict "no migration budget" scenarios—still plan an exit strategy
Important interview questions and answers
- Q: Can ASP.NET Core run on Linux?
A: Yes—Kestrel and the .NET runtime are cross-platform; IIS is optional on Windows. - Q: Is .NET Framework dead?
A: In maintenance mode—new web projects should target .NET 8+ unless blocked by dependencies. - Q: ASP.NET Core vs Node.js?
A: Node excels at I/O-heavy JS stacks; ASP.NET offers strong typing, compile-time checks, and enterprise .NET ecosystems—compare team skills and hosting.
Self-check
- Give one reason to choose ASP.NET Core for a new API.
- Why might an old WebForms app stay on .NET Framework temporarily?
Interview prep
- When choose ASP.NET Core over .NET Framework?
New cross-platform projects, Linux/Docker deployments, and modern LTS releases—legacy Framework only when blocked by unmigrated dependencies.