What is DotNet?

DotNet (pronounced “dot net”) is a free, open-source development platform created by Microsoft that lets you build many kinds of applications-websites, mobile apps, desktop programs, games, and more. It provides a collection of tools, libraries, and a runtime that runs the code you write on Windows, Linux, and macOS.

Let's break it down

  • DotNet: the name of the platform.
  • free, open-source: you don’t pay for it and you can see and change its source code.
  • development platform: a set of tools that help you write software.
  • created by Microsoft: the company that built and maintains it.
  • build many kinds of applications: you can make websites, phone apps, desktop programs, games, etc.
  • collection of tools, libraries, runtime: ready-made code (libraries) plus a system that runs your code (runtime).
  • runs on Windows, Linux, macOS: works on the three main computer operating systems.

Why does it matter?

Because it lets you write code once and run it anywhere, saving time and money; it has a huge community and many learning resources, making it easy to get help; and it supports modern, beginner-friendly languages like C# and F#.

Where is it used?

  • E-commerce sites such as nopCommerce built on ASP.NET Core.
  • Mobile apps using Xamarin/MAUI, for example the Alaska Airlines app.
  • Cloud services on Azure, like the backend of Microsoft Teams.
  • Desktop applications such as the popular photo editor Paint.NET.

Good things about it

  • Cross-platform: write once, run on Windows, Linux, macOS.
  • Rich standard library: many ready-made functions for common tasks.
  • Strong performance: compiled code runs fast.
  • Integrated tooling: Visual Studio and VS Code provide powerful debugging and IntelliSense.
  • Large ecosystem: thousands of NuGet packages and active community support.

Not-so-good things

  • Learning curve can be steep for absolute beginners because the ecosystem is large.
  • Some libraries are still Windows-centric, limiting true cross-platform parity.
  • Runtime size can be large, making it harder to use on very small or embedded devices.
  • Frequent updates may require regular maintenance to keep projects up-to-date.