You probably saw the announcement and felt a pang. JetBrains is sunsetting Kotlin Notebook. The comments section is already filling up with the usual funeral dirge — another promising tool killed before its time, another sign that JetBrains doesn’t care about developers who like to explore.
Stop. Breathe. This isn’t a funeral. It’s a course correction that should have happened a year ago.
The best thing JetBrains can do for Kotlin is stop pretending it’s Python.
Let’s be honest about what Kotlin Notebook actually was: a well-intentioned attempt to wedge Kotlin into a data science workflow that Python already owns lock, stock, and barrel. You know it. I know it. The adoption numbers screamed it. Jupyter didn’t become the default for data exploration because it was technically superior — it won because an entire generation of data scientists built their muscle memory around it, and no amount of Kotlin syntactic sugar was going to rewrite that habit.
So JetBrains poured engineering hours into a notebook experience that a tiny sliver of the community used, while the core language — the stuff that actually pays your mortgage — competed for attention. That’s not strategy. That’s vanity.
Every feature you build for a niche you can’t win is a feature stolen from the battlefield you’re already winning.
Here’s what nobody’s saying out loud: Kotlin’s real war isn’t against Python. It never was. Kotlin’s war is against Java’s legacy baggage on the backend, against Swift’s grip on native iOS, and against the chaotic fragmentation of cross-platform mobile development. Those are fights Kotlin can actually win. Those are fights where JetBrains has momentum, community passion, and a genuine technological edge.
Data science? That’s Python’s hill. Let Python die on it if the AI hype cycle ever turns. Kotlin doesn’t need that corpse.
I get the nostalgia. Some of you genuinely loved opening a Kotlin Notebook, writing a few lines of expressive code, and seeing results inline. It felt modern. It felt like the language was growing up, reaching into new territories. There’s a real grief in watching a tool you enjoyed get shelved.
But grief for a feature is not the same as grief for a language’s future — and confusing the two is how ecosystems die.
Think about what JetBrains is actually signaling here. They’re saying: we know who we are. We know what Kotlin is for. It’s for backend services that need to be maintainable in five years. It’s for Android apps that ship to a billion devices. It’s for Kotlin Multiplatform projects that let one team target iOS and Android without rewriting everything twice. It’s for compiling to native and running fast.
That’s not a retreat. That’s a company that finally read its own strategy document.
The developers who should be worried aren’t the ones losing a notebook. They’re the ones who bet their data science career on a JVM language that was never going to unseat Python in the spaces where Python has institutional gravity — academia, research, the entire ML ecosystem, every tutorial on YouTube. If you’re doing data exploration, use Python. If you’re building production systems, use Kotlin. These are not contradictory statements. They’re just honest ones.
The most dangerous thing a language can do is try to be everything to everyone — because the language that tries to be everywhere ends up being nowhere that matters.
JetBrains has limited resources. You know this because you’ve felt it — the bugs that linger, the features that ship half-baked, the K2 compiler migration that felt like it took a geological epoch. Every hour spent polishing a notebook UI that 2% of users touched was an hour not spent making Kotlin Multiplatform stable enough to trust in production. Every sprint dedicated to DataFrame integration was a sprint stolen from making the compiler faster, the tooling smarter, the Android story tighter.
Now those hours come home.
If you’re a Kotlin developer reading this, here’s what it means for you: double down. The language you chose is getting sharper, not narrower. JetBrains is trimming the fat so the muscle can grow. Your backend skills are more valuable, not less. Your mobile expertise just became more strategic. The ecosystem is maturing — and mature ecosystems cut what doesn’t serve the majority.
Maturity isn’t about adding features. It’s about having the courage to remove the ones that don’t belong.
Kotlin Notebook is dead. Long live Kotlin — focused, unapologetic, and finally honest about what it’s for.
FAQ
Q: But what about developers who actually used Kotlin Notebook for real work?
A: They exist, and they're a small, passionate minority. JetBrains will likely provide migration paths or keep the plugin minimally maintained. But a tool used by a fraction of the community can't justify ongoing engineering investment at the expense of features that serve the majority.
Q: Should I still learn Kotlin if I'm interested in data science?
A: No. If data science is your primary career path, Python is the only rational choice. Kotlin's strength is in building production-grade systems — backends, Android apps, cross-platform mobile. Conflating those two domains is how you end up mediocre at both.
Q: Isn't this just JetBrains giving up on ambition?
A: No — it's JetBrains choosing ambition over vanity. Trying to compete with Python in data science would have been a decade-long losing battle. Focusing on backend, mobile, and native compilation is where Kotlin has genuine momentum and a real shot at dominance. Strategy is about knowing which fights to walk away from.