The .NET SDK and .NET Runtime are two major components of the .NET ecosystem. They serve different purposes during development and runtime of .NET applications.
1. .NET Runtime – “Just Run the App”
Purpose:
The .NET Runtime is what you need to run applications that are built with .NET. It contains everything required to execute .NET apps: the Common Language Runtime (CLR), base libraries, and other components needed at runtime.
Use Case:
Install this if you’re only running a .NET application and not building or compiling any code.
Components:
- CLR (Common Language Runtime)
- Core libraries (e.g., System.*, Microsoft.*)
- JIT (Just-In-Time) compiler
- Garbage Collector (GC)
.NET Runtime Code Example:
Imagine you downloaded a .NET-based app like a dashboard or internal tool built by your company. You just want to run it. Installing the .NET Runtime is sufficient in this case
dotnet myApp.dll2. .NET SDK – “Develop and Build the App”
Purpose:
The .NET SDK includes all essentials you need to build, develop, test, and publish .NET applications. It includes the .NET Runtime, but also adds compilers, command-line tools, project templates, and debugging utilities.
Use Case:
Install this if you’re a developer, writing, compiling, testing, or deploying .NET applications.
Components:
- Everything in the .NET Runtime
- C# / F# / VB compilers
- dotnet CLI (e.g., dotnet build, dotnet run, dotnet publish)
- Project templates (like ASP.NET Web API, Console App, etc.)
Example:
If you’re creating a new web application or console app, you need the .NET SDK.
.NET SDK and .NET Runtime Real-Life Use Case Comparison
Scenario 1: Deployment Server
You’re deploying a production-ready .NET Web API to a Linux server. You don’t need to build it there—only to run it.
Install: .NET Runtime
Scenario 2: Developer Machine
You’re writing code in Visual Studio or VS Code and building .NET apps.
Install: .NET SDK
Summary
.NET SDK and .NET Runtime Comparison Table
| Feature | .NET Runtime | .NET SDK |
| Purpose | Run existing apps | Build, develop, test, and run apps |
| Includes | CLR + base libraries | .NET Runtime + compilers + CLI tools |
| CLI Tools (dotnet) | Limited (dotnet only for running) | Full support (dotnet new, build, run, etc.) |
| Suitable for | End-users, servers for deployment | Developers |
| File Size | Smaller (~50–70MB) | Larger (~300–400MB) |
Understanding the distinction between the .NET Runtime and SDK is critical for efficient application deployment and development. If you’re just running apps, the Runtime is all you need. But if you’re building and shipping code, the SDK is your complete toolbox.
