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Kotlin by JetBrains — Visual Studio Marketplace
v0.0.4 Alpha · Publisher: JetBrains · Free · VS Code ^1.96.0 · Kotlin JVM Gradle & Maven
Kotlin by JetBrains for VS Code: full IDEA intelligence, Alpha caveats
JetBrains shipped an official VS Code extension at KotlinConf 2026 that brings 14 IntelliJ IDEA-grade Kotlin features — completions, diagnostics, navigation, refactoring, call hierarchy, and more — to VS Code via a Kotlin Language Server running on the JVM. Includes install steps, the full feature table, key settings, and five honest Alpha limitations.
JetBrains announced a lot at KotlinConf 2026 in Munich. The item that matters most for VS Code users landed on May 22: Kotlin by JetBrains (
JetBrains.kotlin-server), an official VS Code extension that wires the full IntelliJ IDEA code-analysis engine into the editor via LSP (Language Server Protocol). 1This isn't a syntax-highlighter or a community project. The extension runs a Kotlin Language Server on the JVM and connects it to VS Code — the same analysis backend that powers IntelliJ IDEA's Kotlin plugin. You get IDEA-grade completions, inspections, and quick-fixes without leaving VS Code.
The catch: it's Alpha. KMP projects are not supported yet, and the open GitHub issues at launch include a JVM process bug and a Linux installer error. If your project is a Kotlin JVM Gradle or Maven app, read on. If it's Kotlin Multiplatform, hold off for a few releases.
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Install
Search Kotlin by JetBrains in the Extensions panel, or install by identifier: 2
JetBrains.kotlin-serverRequirements: VS Code 1.96.0 or later. No JDK required for the VS Code extension — the language server ships with its own JVM runtime. Homebrew users who want the standalone CLI can also install it separately:
brew install JetBrains/utils/kotlin-lspIf you have the old extension installed: the previous community extension used the ID
jetbrains.kotlin (note the lowercase publisher). When you install the new one, VS Code shows a conflict dialog asking you to uninstall the old version. Accept it and reload the window — the new extension won't activate until the old one is gone. 2
After install, open your Kotlin JVM project folder, open any
.kt file, and wait. The language server starts indexing in the background — completion and diagnostics activate once indexing finishes. The first run takes longer; subsequent activations are faster once the index is cached.What you get: 14 LSP features
The extension ships 14 features driven by the IntelliJ IDEA Kotlin plugin, not a separate implementation: 2
| Feature | Notes |
|---|---|
| Code completion & signature help | Ranking matches IntelliJ IDEA; completion latency improved ~30% in v261.13587.0 |
| Diagnostics, inspections, quick-fixes | Covers standard Kotlin and kotlinx libraries (Kotlin extended standard library) |
| Semantic highlighting | Token-level, not just regex-based |
| Type & parameter inlay hints | Toggleable per hint type via jetbrains.kotlin.hints.* settings |
| Go to definition / references / type / implementation | Full navigation quartet |
| Call hierarchy | textDocument/prepareCallHierarchy — shows callers and callees |
| Document & workspace symbols | Searchable across the whole project |
| Hover documentation | KDoc rendered inline |
| Organize imports | Removes unused, sorts remaining |
| Rename refactoring | Project-wide, not just in-file |
| Code formatting | IDEA style applied on format-document |
| Code folding | Functions, classes, imports, block comments |
| Build system support | Gradle (stable), Maven (stable), AGP (experimental) |
| Kotlin file templates | IntelliJ-style templates with predefined variables and conditionals |
The completions and inspections come from the same IntelliJ code-analysis engine, so the quality ceiling is genuinely different from what third-party Kotlin LSP implementations offer. u/AlexVie on Reddit (a Neovim user who tried the standalone LSP) put it this way:
"It can be painfully slow at times and auto-complete is a bit buggy. ... the fact that there now IS a LSP that gives almost all the inspections from IDEA is already a step forward." 4
Configure inlay hints and the build tool
The most useful settings out of the box:
{
"jetbrains.kotlin.hints.typeHints": true,
"jetbrains.kotlin.hints.parameterHints": false,
"jetbrains.templates.kotlin.fileHeader": "// Created by ${USER} on ${DATE}",
"intellij.buildTool": "gradle"
}intellij.buildTool tells the language server which importer to use when both a pom.xml and build.gradle exist in the same project. Set it to "maven" or "gradle" — if you leave it unset the server picks one automatically. 5Note the namespace: in v262.4739.0 the build tool setting moved from
kotlinLSP.* to intellij.*. If you copied a settings snippet from an older blog post, that's where the mismatch will be.Known limitations
This is Alpha software and the limitations are real, not boilerplate disclaimers:
- No KMP support. Only Kotlin JVM projects work (Gradle or Maven). Kotlin Multiplatform is listed as "coming in future releases" with no date. u/lppedd on Reddit (+14 upvotes): "Is there a timeline for Multiplatform support? This is probably the missing piece for more widespread Kotlin usage." 4
- Experimental AGP (Android Gradle Plugin) support. Android projects can be imported but this path is marked experimental on the Marketplace page. 2
- Experimental DAP debugger. v262.4739.0 added Debug Adapter Protocol support — attach to a running JVM, set breakpoints, inspect variables. The RELEASES.md warning is explicit: "The features listed in this section are not finalized. They may contain bugs and are likely to change significantly in future releases — do not depend on their current behavior." 5
- Active bugs at launch. GitHub issue #205 (JVM server process respawning on failed initialization) and #208 (Linux install error) were filed the same week as the KotlinConf announcement. macOS users on older hardware may hit #194, where Gatekeeper blocks the
intellij-serverbinary on first run. 6 - Partially closed source. The language server core uses components from JetBrains Air and Fleet. The GitHub repository (
Kotlin/kotlin-lsp, Apache-2.0) is a read-only mirror — documentation PRs are accepted, but code contributions are not. 3
The team's own framing from the README: "The core implementation details and general architecture are mostly settled and stable. Upcoming releases will focus on feature completeness and stability of the existing functionality." 3
Adoption signals
As of May 24, 2026 — two days after the KotlinConf announcement, sixteen days after the initial v0.0.1 listing — the extension has 1,134 installs, 280 downloads, and a 5.0 rating from 3 reviews on the VS Code Marketplace. 2 The GitHub repository (
Kotlin/kotlin-lsp) has 3,300+ stars, 80 forks, and 64 contributors. 3These numbers reflect early adopters, not broad adoption. The install count will shift substantially once more Kotlin developers try it post-conference. The 5.0 rating at this stage reflects enthusiasm from early testers rather than a stable quality baseline.
Alyona Chernyaeva, the JetBrains engineer who wrote the announcement post, framed the release directly: "IntelliJ IDEA and Android Studio remain the most complete environments for Kotlin development. But not every Kotlin developer uses either IDE — some prefer VS Code." 1
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Context: JetBrains' two-step VS Code strategy
This is the second JetBrains Kotlin tool for VS Code in 2026. In February, JetBrains shipped the Java to Kotlin Converter (
JetBrains.j2k-vscode), an LLM-assisted extension that converts Java files to idiomatic Kotlin via right-click. 7 The two extensions are complementary: J2K handles migration, kotlin-server handles day-to-day editing. JetBrains' stated goal is consistent Kotlin tooling "across any editor, any build tool, any agent framework" — the KotlinConf keynote positioned Kotlin Language Server alongside the new Kotlin Toolchain and Documentation Model as three coordinated infrastructure releases. 8Plugin: Kotlin by JetBrains · Publisher: JetBrains · Version: 0.0.4 Alpha · License: JetBrains Free Plugin License
Language: Kotlin · IDE: VS Code ^1.96.0 · Use case: Language server — completions, diagnostics, navigation, refactoring
Install: JetBrains.kotlin-server on VS Code Marketplace · GitHub
Cover image: from KotlinConf'26 Keynote Highlights
References
- 1Official Kotlin Support for Visual Studio Code Is Now Available in Alpha
- 2Kotlin by JetBrains — Visual Studio Marketplace
- 3GitHub — Kotlin/kotlin-lsp README
- 4r/Kotlin — Official Kotlin Support for VS Code Alpha
- 5kotlin-lsp RELEASES.md
- 6Issues · Kotlin/kotlin-lsp
- 7Java to Kotlin Conversion Comes to Visual Studio Code
- 8KotlinConf'26 Keynote Highlights
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