An introduction to .NET Core and how it differs from the .NET Framework

NET Core vs Framework

Before we talk about .NET Core, it will be helpful to understand what is .NET in basic, it’s evolution, different development phases, the limitations, the rise of .NET Core and it’s capabilities as of Dec 2022.

.NET Framework – The journey

.NET is a software framework that is designed and developed by Microsoft. The first version of the .Net framework was 1.0 which came in the year 2002. In easy words, it is a virtual machine for compiling and executing programs written in different languages like C#, VB.Net, etc.

It is used to develop Form-based applications, Web-based applications, and Web services. There is a variety of programming languages available on the .Net platform, VB.Net and C# being the most common ones. It is used to build applications for Windows, phones, web, etc. It provides a lot of functionalities and also supports industry standards.

.NET Framework supports more than 60 programming languages of which 11 programming languages are designed and developed by Microsoft.


Development Phases of .NET Framework

There are different development phases of .NET Framework as below image.

Net 1


OLE Technology: OLE (Object Linking and Embedding) is one of the technologies of Microsoft’s component document. Basically, its main purpose is to link elements from different applications with each other.

COM Technology: The technology of the Microsoft Windows family of the operating system, Microsoft COM (Common Object Model) enables various software components to communicate. COM is mostly used by developers for various purposes like creating reusable software components, linking components together to build applications, and also taking advantage of Windows services. The objects of COM can be created with a wide range of programming languages.

.NET Technology: .NET technology of collection or set of technologies to develop windows and web applications. The technology of .NET is developed by Microsoft and was launched in Feb. 2002, by basic definition, Microsoft’s new Internet Strategy. It was originally called NGWS (Next Generation Web Services). It is considered to be one of the most powerful, popular, and very useful Internet Technology available today.


.NET Architecture

Common language specification (CLS) defines how objects are implemented so they work everywhere .NET works. CLS is a subset of Common Type System (CTS) – which sets a common way to describe all types

Framework class library (FCL) is a standard library that collects reusable classes, interfaces and value types

Common language runtime (CLR) is the virtual machine that runs the framework and manages the execution of .NET programs

Visual Studio is used to create standalone applications, interactive websites, web applications and web services


.NET Core – The Start of The New Era

.NET Core is a newer version of the .NET domain that addresses the limitation of the .NET Framework. .NET Core is a cross-platform framework that can be run for Windows, macOS, and Linux. Moreover, it is open-source and accepts contributions from the developer’s community.

In November 2020, Microsoft released .NET 5.0, dropping the “Core” branding. .NET 6.0, was released in November 2021. The most recent version 7.0 released in Dec 2022. Despite this, for clarity, this article will continue to leverage the “Core” branding to differentiate .NET Core vs. .NET Framework.

The good thing about the two frameworks is their ability to share codes and many components when requested. Yet, the .NET Core and the .NET Framework differences must be analyzed before choosing a .NET development company for your next project.


.NET Core – At the High Level

.NET is a free, cross-platform, open source developer platform for building many kinds of applications. .NET is built on a high-performance runtime that is used in production by many high-scale apps.


Cloud apps


Cross-platform client apps


Windows apps


Other app types

Key Differences in .NET Core Vs .NET Framework

To determine which is better, .NET Core or .NET Framework, here are some parameters that draw the line between the two Microsoft frameworks.


1. Compatibility

The best thing that makes .NET Core the number one in its league is its compatibility with various operating systems — Windows, Linux, and macOS. The .NET’s structure was fully re-architected to give birth to .NET Core to help businesses develop applications on all platforms.

Regarding .NET web development services for enterprises, deploying .NET Core that supports primarily used platforms besides Windows can be suitable. The .NET Core performance is quite impressive, and an added perk is its open-source attribute that makes it the most popular framework in the application development space.

On the other hand, the .NET Framework supports a restrictive model, which allows running websites, apps, and web services only on the Windows operating system. Within the cross-platform framework space, the .NET Framework is recommended only when an organization deploys the framework for a long time.

A note for organizations and developers — Microsoft has parceled out the source code for WPF, Windows Forms, and WinUI.


2. Performance

When a performance-oriented and scalable system is the topmost priority, who wins the .NET Core Vs. .NET Framework performance battle?

The most recent version of .NET Core demonstrates high scalability and performance. It is recommended by Microsoft with ASP.NET Core as the optimal choice for high-performance system needs, mainly where microservices may be involved. In several independent tests, .NET Core vs. .NET Framework performance has been tested, with one test demonstrating 7 to 13 times faster.

The .NET Core has a recompilation feature to optimize compiled code without changes, making it easier for developers to test and deploy code. The most recent versions of .NET Core (6 and 7) have a massive focus on improving performance.


3. Deployment Model

One of the essential features available in .NET Core is its flexible deployment model. It means whenever the latest version of .NET Core gets launched; it can be instantly updated on one machine at a time, thereby getting uploaded to new directories without affecting the existing applications. Moreover, .NET Core can also be deployed for apps requiring more isolation using the new app bundling tools.

Regarding the .NET Framework, the web application must be deployed only on the Internet Information Server. However, .NET Core’s advantage over .NET Framework lies in the fact that it can be hosted in more than one way, making it more flexible.


4. Focus on devices

In today’s highly progressive digitized tech-friendly world, no matter what an application’s business domain is, it becomes essential to build an app that can reach different markets and end-users wrapped in the latest technology. And .NET Core aims to achieve this target – to develop apps in many domains, such as gaming, mobile, IoT, and AI – with continuous updates to .NET Core to respond to emerging opportunities.

.NET 7 (the most recent version) includes an integrated platform for developing applications for the cloud, IoT, and mobile. Microsoft also recently announced ML.NET 1.4, a Machine Learning framework to build web apps and desktop apps focused on data science. The .NET ecosystem can also extend to the Blazor framework, which helps build single-page applications (SPAs) leveraging . NET.

In contrast, the .NET Framework is limited only to Windows OS.


5. Source

Another factor to consider in the question of .Net Framework vs. .NET Core is whether these are open-source or not.

.NET Core is open-source, while .NET Framework is proprietary and released under the Microsoft Reference Source License, though it includes some open-source components.


6. Support for Microservices and REST Services

.NET Core does not support WCF (Windows Communication Foundation) services, always requiring creating a REST API to implement microservices.

In contrast, the .NET Framework gets support from WCF and also supports REST Services but does not support the creation or deployment of microservices and is less effective regarding performance and scalability.


7. Security

.NET Framework leverages the Windows security model and leverages Code Access Security, kept up to date by Microsoft with the latest security patches.

.NET Core may lack Code Access Security, but it uses a more flexible and modern security model, resulting in a more secure option.


8. Packaging & Shipping

The .NET Framework must be installed as a single package for Windows. In contrast, .NET Core is packaged and shipped independently of the underlying operating system via the NuGet package manager.


9. CLI tools

.NET Core provides a lightweight cross-platform Common Language Infrastructure (CLI), with an option to switch to an integrated development environment (IDE) such as Visual Studio.

The .NET Framework also contains CLI tools, with programs written for .NET Framework compiled into Common Intermediate Language code (CIL) instead of being directly compiled to machine code.


10. Mobile Development

As a Windows-only framework, the .NET Framework does not support mobile development, making this framework very inflexible for the needs of today’s applications.

However, .NET Core does have some support for mobile apps, particularly given the shared connection/compatibility with Xamarin and other open-source platforms for developing mobile applications.


11. Application Models

The .NET Framework Application Model includes WinForms, ASP.NET, and WPF, used for developing desktop and web apps.

In contrast, .NET Core does not support desktop application development, focusing instead on the web, windows mobile, and windows store with ASP.NET and Windows universal apps.


Code-Execution Process in .NET Framework

Net 2


Choosing a Compiler

It is a multi-language execution environment, the runtime supports a wide variety of data types and language features.

To obtain the benefits provided by the common language runtime, you must use one or more language compilers that target the runtime.


Compiling your code to MSIL

Compiling translates your source code into Microsoft Intermediate Language (MSIL) and generates the required metadata.

Metadata describes the types in your code, including the definition of each type, the signatures of each type’s members, the members that your code references, and other data that the runtime uses at execution time.

The runtime locates and extracts the metadata from the file as well as from framework class libraries (FCL) as needed during execution.


Compiling MSIL to Native Code

At execution time, a just-in-time (JIT) compiler translates the MSIL into native code.

During this compilation, code must pass a verification process that examines the MSIL and metadata to find out whether the code can be determined to be type safe.


Running Code

The common language runtime provides the infrastructure that enables the execution to take place and services that can be used during execution.

During execution, managed code receives services such as garbage collection, security, interoperability with unmanaged code, cross-language debugging support, and enhanced deployment and versioning support.


Code-Execution Process in .NET Core

Net 3

  • In .NET Core now we have a new series of compilers, like we have Roslyn for C# and VB.
  • You can also make use of the new F# 4.1 compiler if you want to use F# with .NET Core.
  • Actually these tools are different and we can use Roslyn with .NET Framework as well if we are using C# 6 or later, because C# compiler can only support up to C# 5.
  • In .NET Core, we don’t have a framework class libraries (FCL), so a different set of libraries are used and we now have CoreFx.
  • CoreFx is the reimplementation of the class libraries for .NET Core.
  • We also have a new run time with .NET Core known as CoreCLR and leverages a JIT Compiler.
  • Now the question is why do we have the reimplementation of all these components that we already have in .NET framework.
  • So the answer is the same as why Microsoft implemented .NET Core.


.NET Framework vs .NET Core: Which Should You Pick, and When?

After comparing .NET and .NET Core side by side, you might think .NET Core definitely seems to have a great edge over the .NET Framework by saving developers’ resources and time.

But in reality, both platforms are distinctive in their own ways, and deciding which is the better one depends on your project requirements.

Nonetheless, let us figure out what sort of apps you will be able to create with both these technologies.


Go for the .NET Framework when the app:

  • Is for large-scale enterprise or desktop use
  • Runs only on the Windows platform
  • Is already running on .NET Framework
  • Uses third-party libraries
  • Needs technologies like WCF, webforms, or workflow that are not compatible with .NET Core
  • Deploys on non-.NET Core cloud services like Azure App Service


Go for.NET Core when the app:

  • Required to be cross-platform compatible
  • Needs to be highly scalable and performance-oriented
  • Uses microservices or container technologies like Kubernetes and Docker
  • Depends heavily on CLI control
  • Executes several .NET versions on the same server
  • Needs developers who are okay with an extensive learning curve


Final Thoughts on .NET vs .NET Core

Without any doubt, the debate about .NET Core vs .NET Framework is here to stay. Both are progressive solutions and unique in their exclusive fields. That being said, Microsoft is continuously innovating to upgrade both platforms, so while choosing one, you may find yourself on the fence.

Regardless of all the nos, ifs, and buts, the future of the .NET world is more promising than ever. We suggest that you make the decision based on your project scope, development needs, and budget.