Why Microsoft rebuilt .NET

.NET & AI Newsletter · by Mukesh Murugan · 3 min read

If you have ever tried to explain .NET to a developer who last used it around 2014, you know how hard it is. Most of them still think it only runs on Windows, and the naming over the years does not help either.

Last week I published a short video that explains exactly this, in about five minutes.

The video opens with a small API built with .NET 10. In my tests, the Native AOT build answers its first request in about 32 milliseconds, uses around 18 MB of memory, and ships as a single 9 MB file that runs on Linux without installing any runtime. The normal build of the same API took about 145 milliseconds and 62 MB.

If you last looked at .NET around 2014, those numbers probably sound wrong. Getting from there to here meant Microsoft had to take a framework they had been building for over a decade and rebuild it from scratch. The video walks through why they did that, and what it means for you if you are choosing a stack today.

The code you need to get started is still tiny. This is the whole Program file you get from the empty web template:

// dotnet new web
var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();

app.MapGet("/", () => "Hello World!");

app.Run();

The response to this video surprised me. It crossed 57,000 views in its first five days, which is more than any other video on my channel, and a lot of the comments came from developers outside .NET, including Java developers. A short, clear explainer turns out to be useful even if you already know .NET, because it gives you something simple to send to a teammate or a friend who still thinks .NET is Windows-only.

Includes my own Native AOT vs normal build numbers from .NET 10.

This video is the first of many. From now on, I will be posting on YouTube regularly, with a short animated explainer like this one every week and a longer hands-on tutorial every other week, all about .NET, EF Core, Web APIs and AI.

The next video, Life of a .NET Developer, goes live today. It is about the curve almost every .NET developer goes through, where you keep adding patterns until the project is far more complex than the problem it solves, and then slowly take most of them back out. Where you are on that curve right now might surprise you.

If you enjoy learning this way, please subscribe to my YouTube channel so you do not miss it. It is free, and it helps the channel a lot.

And if you have not watched it yet, this is the one to start with → .NET in 5 Minutes: Why Microsoft Rebuilt It From Scratch

Thanks for reading, and happy coding!
- Mukesh

Free courses, always open: .NET Web API: Zero to Hero · Claude Code for .NET Developers