scalafmt

Format files

$ scalafmt [file.scala]

$ scalafmt -i [file.scala]

$ scalafmt --check [file.scala]

$ scalafmt [src/]

$ scalafmt -c [.scalafmt.conf] [file.scala]

$ scalafmt --diff [file.scala]

$ cat [file.scala] | scalafmt --stdin

scalafmt [-i] [--check] [-c config] [options] [files]

scalafmt is an opinionated code formatter for Scala that enforces consistent style across projects. It reformats source code according to configurable rules covering line length, indentation, alignment, and import ordering, supporting both Scala 2 and Scala 3 syntax through dialect configuration.
The --check mode verifies formatting without modifying files, returning a non-zero exit code when changes would be made, which is useful for CI pipeline enforcement. The -i (in-place) mode directly modifies files during development. Configuration is defined in a .scalafmt.conf file at the project root using HOCON format.

-i, --inplace

Modify files in place.

Check only, no changes.

Config file.

Show changes.

Read from stdin.

Write to stdout.

Exclude files.

Show help.

.scalafmt.conf

Project-level configuration file in HOCON format defining formatting rules including maxColumn, dialect, align settings, and rewrite rules.

May change code structure subtly. Configuration options are many. Editor integration recommended.

scalafmt was created by Olafur Pall Geirsson for Scala formatting. It's widely used in the Scala ecosystem for code style enforcement.

scala(1), sbt(1), metals(1)