Framework Review: Ktor

I’ve used many frameworks in my years of developing software. With that, I’ve decided to write a series on various frameworks to help those looking into the dizzying amount of framework choices for their next project.

My next review is on a Kotlin web framework from JetBrains, Ktor.

What is Ktor?

Ktor is a web framework built by the people we can thank for birthing Kotlin, JetBrains.

Ktor actually comes in two flavors, client and server, this article will be purely focusing on the server piece.

Ktor exists as a means to add a pure Kotlin solution to the market, seeing that you otherwise have Java frameworks that simply support Kotlin.

What do I like about Ktor?

The main thing I like about Ktor is how simple it is to get up and running. you go to their project builder page and pick out which components you want to use and you now have a project to build off of.

Now I know this is not ground breaking, seeing that Spring also has their own project builder, but the thing I really liked was that they give you sample code to help you get a feel on how to build your web app.

Their documentation is also really good, it gives you enough information, that it made it easy for me to figure out how the components work.

Something I really like about Ktor is that it’s very unopinionated, meaning there’s no direct structure you need to follow, you can make it how you want, which if you don’t like being confined to a framework’s set structure, you will enjoy that aspect of Ktor.

Being a JetBrain product, they will of course give first class support of Kotlin libraries they wrote themselves, which if you’re a fan of their various Kotlin libraries (which I fall into that group) this is a giant win, this doesn’t mean you can’t use another library, but it may mean a little more work if you get into a bind if something is not automatically working.

What do I not like about Ktor?

While Ktor is really nice and simple, you may find that simplicity to be a burden if you’re writing an enterprise application. Unlike Spring, it largely leaves you to figure out what you want to build.

While this isn’t directly about Ktor, I feel like mentioning it since they advertise it in their docs, but I’m not a big fan of JetBrains’ Expose library, it works, but the fact it doesn’t have a baked-in migrations system, makes it something I’d think twice about using (they have a super basic API, but they should really consider having something better).

A minor gripe, and one that I think will improve in time, is that there’s not a lot of great tutorials or articles on Ktor, I’m guessing it’s due to how new Ktor is, so I expect that this problem will be resolved in time as people find out what Ktor is and how it can be a viable option for their project.

Conclusion

Ktor is a great choice for developers who are looking for a pure Kotlin framework and also love being able to forge their own path and doesn’t need a heavy framework that has all sorts of rules and best practices, but if you plan on making a rather complex application that having some baked-in components and structure would be beneficial, then you may be better off sticking with something like Spring.

I personally enjoyed playing around with Ktor and I can totally see myself using it on a future side project, I appreciate how simple it is and how light it is and most of all that it’s a pure Kotlin offering in a sea of web frameworks that’s usually Java first.