Beginner to Advanced
C# Mastery — Zero to Advanced .NET Engineer
From your first program through LINQ, async, testing and ASP.NET Core to the runtime, performance and architecture. Every compiler message and program output in the lessons was captured from a real .NET 10 SDK.
The course
Not loading? Open the course in its own tab. It carries the captured output of every lab, so the first load is large.
Common questions
Can I run C# on this page?
No. The page cannot compile C#. You edit the code here, export it as a .zip and run it with your own .NET 10 SDK, then compare with the output captured from a real run.
How are the exercises checked?
Each exercise comes with a check program that you run on your machine. Every starter was run and fails, and every reference solution was run and passes. The page cannot see your result, so marking an exercise as passed is your own report.
Which versions and platforms were tested?
C# 14 on .NET 10, with SDK 10.0.113 on Ubuntu 24.04 x64. Windows, macOS and arm64 were not run. The code is intended to be portable, and the Register tab shows the exact environment.
Has the course been reviewed by a .NET expert?
Not yet. The output is captured from real runs and the line-by-line tables are checked against the code by machine, but no independent expert has reviewed the explanations. The Report tab lists what was verified and what was not.
Is the C# course free?
Yes. All 120 lessons, the exercises and the quizzes are free and need no account.