.NET Framework vs .NET Core differences
What are the key differences between .NET Framework and .NET Core / modern .NET that interviewers expect?
Answers use simple, clear English.
Quick interview answer
.NET Framework is Windows-only, ships with OS/IIS, uses System.Web, AppDomains, GAC, web.config. .NET Core / .NET 5+ is cross-platform, open source, side-by-side runtimes, Kestrel + middleware, built-in DI/logging/config, SDK-style projects, containers-first. Performance and deployment models differ; APIs overlap but are not identical (especially ASP.NET).
Detailed answer
.NET Framework is Windows-only, ships with OS/IIS, uses System.Web, AppDomains, GAC, web.config. .NET Core / .NET 5+ is cross-platform, open source, side-by-side runtimes, Kestrel + middleware, built-in DI/logging/config, SDK-style projects, containers-first. Performance and deployment models differ; APIs overlap but are not identical (especially ASP.NET).
Real example & use case
New microservices on .NET 8 Linux containers; legacy payroll stays on Framework 4.8 IIS until strangled.
Pros & cons
Pros of Core: portability, speed, modern tooling. Cons: migration cost for System.Web/WCF-heavy apps.