[amazingamazing]

I’m not sure why you’re so obsessed with this. You can do the same thing with any validation library in nodejs. Your exact example is possible by integrating any validation library of your choosing into a nest js route pipe. In particular primitive type validation is built into nestjs anyway

The fact that it’s built in is neat but not really important. Most people are not making thousands of toy apps. If the necessary they will integrate and move on.

There are more compelling reasons to use .net than this.