The difference between ASP.NET and ASP.NET Core is significant in terms of architecture, performance, cross-platform support, flexibility, and modern development practices. Here's a detailed comparison:
1. Platform Support
| Feature |
ASP.NET |
ASP.NET Core |
| Platform |
Windows only |
Cross-platform (Windows, macOS, Linux) |
| Runtime |
.NET Framework |
.NET Core (now part of .NET 5/6/7/8+) |
2. Architecture
| Feature |
ASP.NET |
ASP.NET Core |
| Modular Framework |
Monolithic |
Modular, using NuGet packages |
| Hosting Dependency |
IIS only |
Can be hosted on IIS, Kestrel, Docker, or self-hosted |
| Middleware |
Based on HttpModules and HttpHandlers |
Lightweight and flexible middleware pipeline (via UseMiddleware) |
| Configuration System |
Web.config (XML) |
appsettings.json, environment variables, command-line args |
3. Performance
| Feature |
ASP.NET |
ASP.NET Core |
| Speed |
Slower due to older architecture |
High performance (much faster in benchmarks) |
| Optimization |
Less flexible |
Built-in support for async, minimal APIs, and efficient memory usage |
4. Dependency Injection (DI)
| Feature |
ASP.NET |
ASP.NET Core |
| DI Support |
Not built-in (requires third-party libs) |
Built-in dependency injection container |
5. Development and Maintenance
| Feature |
ASP.NET |
ASP.NET Core |
| Active Development |
In maintenance mode |
Actively developed and updated |
| Razor Pages |
Only in MVC pattern |
Razor Pages for page-focused scenarios |
| Unified Framework |
No (Web Forms, MVC, Web API are separate) |
Yes – Unified MVC/Web API/Razor in one framework |
6. Project Structure & Tools
| Feature |
ASP.NET |
ASP.NET Core |
| Project File |
.csproj (complex XML) |
Simplified .csproj format |
| CLI Tools |
Limited or Visual Studio only |
Powerful .NET CLI |
| Frontend Integration |
Manual |
Built-in support for SPA (Angular, React) templates |
7. Security
| Feature |
ASP.NET |
ASP.NET Core |
| Identity System |
Available, but older |
ASP.NET Core Identity (modern, modular) |
| GDPR, HTTPS, CORS |
Manual or limited support |
Built-in support |
8. Lifecycle and Future
| Feature |
ASP.NET |
ASP.NET Core |
| Future Proof |
Legacy technology |
Future of .NET web development |
| .NET 5+ Support |
Not supported |
Fully supported with latest .NET versions |
Summary Table
| Feature |
ASP.NET |
ASP.NET Core |
| Cross-platform |
❌ |
✅ |
| Performance |
⚠️ Slower |
🚀 Fast |
| Modular Design |
❌ |
✅ |
| Hosting Flexibility |
❌ IIS only |
✅ IIS, Kestrel, Docker, etc. |
| Dependency Injection |
❌ External libraries |
✅ Built-in |
| Middleware Support |
❌ Legacy system |
✅ Lightweight and extensible |
| Modern Web Features |
⚠️ Partial |
✅ Full (CORS, HTTPS, SPA support) |
| Active Development |
❌ Maintenance mode |
✅ Actively evolving |