What is Ktor?
The Ktor (http://ktor.io/) Framework is an open source web framework for quickly building web applications in Kotlin with minimal effort and without needing to set up technology constraints such as dependency injection, logging, and so on. It is made by JetBrains and is still in alpha. It will be stable in upcoming months.
Note
The Kotlin website contains a list of all the web frameworks and to build RESTful web services. It is available at https://kotlin.link/. You can refer to the website and check out other frameworks.
Why Ktor?
Ktor is officially supported by JetBrains, which is one of the reasons to consider going with Ktor when developing web applications in Kotlin. Apart from that, Ktor has three key principles, which make it the framework of choice when building web applications in Kotlin.
Understanding unopinionated applications
The Ktor framework ships with very few setting-up constraints, such as logging, templating, messaging, persistence, serializing, dependency injection...