The reason for Kotlin’s uptick in popularity seems pretty clear: In May, it became an official language for Android, joining C++ and Java. At this year’s edition of its annual I/O conference, Google announced that it was “excited” to work with JetBrains, which created the language.
“We will be partnering with Google to create a non-profit foundation for Kotlin,” JetBrains wrote in a statement on its blog. “Language development will continue to be sponsored by JetBrains, and the Kotlin team (over 40 people and second largest team at the company) will operate as usual.”
Kotlin’s newfound status as a first-tier Android language may have a significant long-term effect on its popularity. The closest analogy may be Swift, the programming language that Apple designed as the successor to Objective-C, its longtime language for iOS and macOS development; soon after its release, Swift began to rapidly climb the TIOBE rankings, propelled in large part by Apple’s aggressive outreach to developers. If Google highlights Kotlin in a similar fashion, it could rocket rapidly up the lists of most-popular programming languages.
But Google and Android aside, Kotlin boasts features that may attract developers in large numbers. “The mixture of expressive power and compilation speed might be the key features of Kotlin to succeed,” TIOBE wrote in a note accompanying the June rankings. “Apart from Kotlin, Hack and Rust are moving up in the top 50 as well.”
TIOBE’s popularity ratings are based on data from a variety of aggregators and search engines, including Google, Wikipedia, YouTube, and Amazon. In order for a language to rank, it must be Turning complete, have its own Wikipedia entry, and earn more than 5,000 hits for +”<language> programming” on Google.