Ktlint Formatter for VS Code

A zero-configuration VS Code extension that formats Kotlin code using ktlint. No setup required - just install and start formatting!

Features

Zero Configuration: No ktlint installation or setup needed
Automatic Setup: Downloads ktlint (v1.8.0) automatically on first use
Native Integration: Works with VS Code's built-in formatting commands
Kotlin Standard: Follows the official Kotlin coding conventions
Script Support: Formats both .kt and .kts files
Status Notifications: Visual feedback on formatting success/failure

Installation

From VS Code Marketplace

Open VS Code
Go to Extensions (Ctrl+Shift+X or Cmd+Shift+X on Mac)
Search for "Ktlint Formatter"
Click "Install"

Or install directly from the VS Code Marketplace

Command Line:

code --install-extension rnoro.vscode-ktlint-formatter

Usage

Manual Formatting

Open any Kotlin file (.kt or .kts) and format using:

Keyboard: Shift + Alt + F (Windows/Linux) or Shift + Option + F (Mac)
Context Menu: Right-click → "Format Document"
Command Palette: Ctrl+Shift+P → "Format Document"

Auto Format on Save

Add to your VS Code settings.json:

{
  "editor.formatOnSave": true,
  "[kotlin]": {
    "editor.defaultFormatter": "rnoro.vscode-ktlint-formatter"
  },
  "[kotlin-script]": {
    "editor.defaultFormatter": "rnoro.vscode-ktlint-formatter"
  }
}

Requirements

VS Code: 1.85.0 or later
Java Runtime: Required to execute ktlint (check with java -version)

How It Works

Extension activates when you open a Kotlin file
On first use, ktlint binary (v1.8.0) is downloaded automatically
Formatting requests are processed through ktlint
Results are applied to your editor with status notifications

Troubleshooting

Formatting doesn't work

Check Output Panel: View → Output → Select "Ktlint Formatter"
Verify Java: Run java -version in terminal
Reload Extension: Press F1 → "Reload Window"

Download fails

Check your internet connection
Verify proxy settings if behind corporate firewall
Check VS Code's network settings

Manual ktlint download location

Ktlint is stored at: ~/.vscode/globalStorage/rnoro.vscode-ktlint-formatter/ktlint

Contributing

Found a bug or have a feature request? Please open an issue on GitHub.

Recommended Extensions

For the best Kotlin development experience in VS Code, use this extension together with:

Kotlin Language Server - Official Kotlin language server from JetBrains
- Provides IntelliSense, code navigation, and refactoring
- Developed and maintained by JetBrains

License

MIT License - see LICENSE for details

Kotlin Ktlint Formatter

rnoro