Kotlin Formatter

Why it's ranked here

Its strongest case is workflow consistency. The editor and build integrations invoke the same command-line implementation, while Git-aware modes operate on staged or committed content instead of blindly checking working files. That makes enforcement practical across local editing and repository gates.

What's good

The pre-commit path preserves partially staged work by formatting Git blobs rather than the entire on-disk file. Dry runs, distinct exit codes, standard-input support, performance statistics, parallel formatting, and configurable binary discovery make the formatter useful in scripts and larger builds.

Tradeoffs

The daemon is explicitly experimental and accepts fewer formatting options than the main command. Java startup is slow enough to motivate that daemon. The IntelliJ integration starts disabled, configuration changes require a restart, and import optimization must remain off for Kotlin files.

How to use it well

It suits Kotlin teams that want identical formatting during editing, Gradle checks, commits, and pushes. Install the command centrally, enable editor formatting, format staged code before commit, then check committed code before push. It does not optimize imports or replace broader static analysis.

Observed

License

Apache License 2.0

Primary language

Kotlin

Interfaces

Command-line tool, IntelliJ IDEA plugin, Gradle plugin, and Git hooks

CLI installation

Hermit package, pre-packaged distribution, or executable fat JAR

Distribution

Artifacts are available through Maven Central and GitHub Releases

Formatting engine

ktfmt using Google formatting style with a 120-character maximum width

Input surfaces

Files, directories, standard input, staged Git content, and committed Git content