Square Open Source ♥s Kotlin

Consumers of Square’s open source libraries may remember our “Seven Days of Open Source” prior to Google I/O 2013. We released major versions of some of our projects in the days leading up to the event. This culminated in us also having a booth inside the developer space at I/O and getting to meet and chat with you all about those projects and others.

While we don’t have seven projects to release this year, we do have a few days of blog posts and releases centered around a common theme: Kotlin!

In January 2015, Kotlin was approved internally at Square for use in our Android applications. Since then we have published the document that made the case for investment and our engineers have spoken at conferences around the world evangelizing the language. In addition to Android apps, new Gradle and IntelliJ plugins are being written in Kotlin. Later this year we’re hoping that Kotlin will also be deployed on the server.

As the language’s usage has grown internally and externally, a few rough edges have emerged with our open source libraries. The blog posts over the next few days will outline some of these problems and they’re paired with corresponding library releases to remedy them.

We’re committed to Kotlin at Square. These changes should help improve the developer experience of our libraries for all of you who have also embraced the language on your platform of choice.

Be sure to check back each day for updates!

• Friday (5/12): Rolling out @Nullable
• Saturday (5/13): Non-null is the Default
• Sunday (5/14): An Optional’s place in Kotlin
• Monday (5/15): Kotlin’s a great language for JSON
• Tuesday (5/16): Generating Kotlin code with KotlinPoet