Koa vs ASP.NET Core

Using generators (a bleeding edge feature, even for Node.js) would clean up your code from the mess caused by all those callbacks; making your code more manageable.

Koa is very lightweight with just 550 lines of code.

Generators functions are of course a huge plus, but at the time Koa team has transcended generations functions and shifted towards async/await style programming. It has made the Koa best framework available in the market.

Koa is developed by the team behind a widely used node.js framework (express.js).

Thanks to breakthroughs in ROSLYN compiler and the efforts of the .NET COre developer team, code written in C# can reach speeds just a step behind C++.

Can run on Windows, Linux and Mac (also Visual Studio Code editor).

In .NET Core 2.1 and 3.0, new APIs are added that make it possible to write JSON APIs that require less memory, using Span<T> and UTF8 strings, and improve throughput of applications like Kestrel, ASP.NET Core web server. See also Utf8JsonReader.

Both microsoft and 3rd party tutorials are mostly of high quality and encourage you to use the industry best-practices.

Built-in middleware featuring: Authentication, Cookie policy, Health Check, MVC, Session etc.

Ability to host on IIS, Nginx, Apache, Docker, or self-host in your own process.

It is a very secure platform.

Both VS and VSCode are powerful free IDEs that are well integrated with ASP.net Core. VS Community also allows for commercial use for projects with less than 5 developers.