JetBrains just dropped news worth paying attention to if you live in the Kotlin ecosystem day to day: Kotlin Notebook is being sunset as an official product starting with IntelliJ IDEA 2026.2. The internal team will stop maintaining the plugin, and development is being fully handed off to the community under an open-source model.
For anyone unfamiliar, Kotlin Notebook was an interactive, Jupyter-style notebook experience but for Kotlin — useful for data exploration, quick prototyping, or trying out snippets without spinning up a full project. Now it’s the one being retired.
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Why the Sunset?
JetBrains’ reasoning is fairly candid: adoption never reached the level they’d hoped for. What stands out more, though, is the mention of how AI tooling has reshaped developer habits — the way people explore code, prototype, and iterate has shifted, and a lot of the workflows that used to drive notebook usage have moved elsewhere.
That tracks. A lot of “let me try this in a notebook before writing real code” behavior has quietly been replaced by AI pairing directly inside the IDE or chat, without needing a separate exploration environment at all.
The Transition Timeline
If you’re still using Kotlin Notebook, here’s what to expect:
- IntelliJ IDEA 2026.1 and earlier — stays bundled as usual, no changes.
- IntelliJ IDEA 2026.2 — the plugin gets unbundled from the IDE. It’s still installable from the Marketplace and compatible with this version, but there won’t be new feature development from the JetBrains team. The source is published on GitHub under Apache License 2.0, so anyone can build and contribute to it independently.
- IntelliJ IDEA 2026.3 and beyond — JetBrains won’t ship a compatible plugin version anymore. From this point on, the project’s survival depends entirely on the community.
During the transition, the Kotlin Jupyter kernel will still get best-effort maintenance from JetBrains, and the support team remains available for compatibility questions. Anyone interested in helping maintain the project can reach out through the #notebooks channel on Kotlin Slack.
What Happens to Kotlin DataFrame?
This is arguably the good news buried inside the sunset announcement. Kotlin DataFrame — the type-safe, notebook-style data transformation library — isn’t going down with Kotlin Notebook. Thanks to a recent compiler plugin, schema-aware APIs and generated column accessors now work directly in regular .kt files, fully wired into Gradle and Maven, with no notebook environment required at all.
In other words, the notebook-style data workflow isn’t disappearing — it’s just moving into regular Kotlin projects. JetBrains also recently shipped Kotlin DataFrame 1.0.0-Beta5 with a batch of improvements across the library.
My Take
I’m not a heavy Kotlin Notebook user myself — most of my day-to-day is Android and Kotlin Multiplatform, while Notebook’s audience skews more toward data science and exploration. But this move is worth watching as a signal: a tool can be conceptually solid and still get trimmed if it doesn’t reach meaningful traction, especially during a moment where developer workflows are shifting fast toward AI-assisted tooling instead of separate exploration environments.
If you do rely on Kotlin Notebook for data workflows, now’s a reasonable time to start moving toward the Kotlin DataFrame approach inside regular projects, before plugin support fully stops at version 2026.3.