[CharlieDigital]

Here is a .NET web API

    var builder = WebApplication.CreateBuilder(args);
    var app = builder.Build();

    app.MapGet("/{userId}", (int userId) => userId);
    app.Run();

See `int userId`? If I call this API with `http://localhost:5123/asdf`, I will get an error because the types don't match. If I call this with `http://localhost:5123/1234` it will work fine. The same would be true if I required a class `User` here. The router is able to introspect the type at runtime to determine if the types match; both basic types like this as well as complex types using the built-in serializer. It is built in.

I've put it into a short clip for you: https://imgur.com/a/WNbGUQD

[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.