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About the Scala Formatter Online Scala Code Formatter

Paste your Scala code, hit "Format" and instantly get clean, consistent, scalafmt-style output. Ideal for backend services, data pipelines, FP libraries, and classroom examples. No config files required – just opinionated, modern Scala formatting ready for review and git commits.

Why Use Our Scala Formatter

  • Instantly format unstructured or misaligned Scala code
  • Fix spacing around types, parameters, and operators
  • Normalize brace style for classes, objects, traits, and methods
  • Apply scalafmt-style line wrapping for long expressions and method chains
  • Supports `.scala`, `.sc` scripts, and `.sbt` build files
  • Code is formatted via a secured backend – not shared or indexed
  • Responsive editor UI that works on laptop, desktop, and tablet

🛠️ How to Format Scala Code Online for scala-formatter

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1. Paste or Load Your Scala Code

📥 Paste your Scala code into the editor or drag-and-drop a `.scala`, `.sc`, or `.sbt` file. The editor applies Scala syntax highlighting so you can quickly scan your code.

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2. Click "Format"

⚙️ Hit the **Format** button. Your code is sent over HTTPS to a scalafmt-style formatter that reorganizes whitespace, indentation, and line breaks without changing semantics.

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3. Review the Result

🔍 Compare the cleaned-up version to your original. Braces, spacing, and blank lines are normalized so the structure of your code is easier to follow.

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4. Copy or Download

📤 Copy the formatted Scala code back into your IDE, or download it as a `.scala` file ready for commit, code review, or deployment.

Technical Specifications

Styling Behavior (Scalafmt-Style)

The formatter aims to mirror common scalafmt conventions so your code looks idiomatic in modern Scala projects.

AspectBehaviorNotes
Indentation & BracesConsistent indentation for `class`, `object`, `trait`, `def`, `if`, `match`, and `for`Makes nested control flow and pattern matches easier to read.
Type & Parameter SpacingNormalizes spaces around colons, arrows and parameter listsFor example: `def f(x: Int): String` instead of `def f(x:Int):String`.
Imports & PackagesKeeps package and import blocks structured and separated from definitionsImproves navigation and consistency across files.
Blank LinesStandardizes blank lines around top-level definitionsSeparates logical sections like models, services and helpers.
IdempotencyRunning formatting multiple times yields the same resultSafe to reformat as often as you like without style drift.

Scala Version Compatibility

The formatter is designed for both Scala 2 and Scala 3 syntax.

FeatureSupportNotes
Scala 2.x✅ YesWorks with common patterns like implicits, companion objects, and classic for-comprehensions.
Scala 3 (Dotty)✅ YesUnderstands given/using, extension methods, enums, and other Scala 3 constructs.
SBT build files✅ YesFormats `.sbt` files used in builds and dependency definitions.

Supported Input & Limits

Optimized for real-world project files, not just tiny snippets.

ParameterLimit / BehaviorNotes
File extensions.scala, .sc, .sbtSource files, scripts and build definitions.
MIME typestext/x-scalaUsed internally for syntax highlighting.
Max input size≈ 2 MB of source codeExtremely large generated code is better formatted via local scalafmt.
EncodingUTF-8 recommendedNon-UTF-8 content should be converted before formatting.

Execution & Safety

Formatting is performed through a private, secured backend instead of public, third-party services.

AspectBehaviorNotes
TransportHTTPS calls to the Scala formatting APIYour code is transmitted securely and not publicly exposed.
Timeout~25 seconds per requestPrevents long-running or stuck formatting jobs on pathological inputs.
SemanticsLayout-only transformationsThe formatter changes whitespace and layout, not your program logic.

Use Scalafmt in Your Local Workflow

For full control and repository-wide formatting, install scalafmt and integrate it into your build or CI pipeline:

Universal (via sbt)

Add scalafmt to your project

addSbtPlugin("org.scalameta" % "sbt-scalafmt" % "2.5.2")

Adds the sbt plugin so you can run scalafmt from the sbt shell.

Format all sources

sbt scalafmtAll

Formats all Scala and sbt files in your project using `.scalafmt.conf`.

Check formatting in CI

sbt scalafmtCheckAll

Fails the build if files are not properly formatted.

Commit a `.scalafmt.conf` file to keep your team, CI and editor integrations all aligned on the same Scala style.

Common Use Cases

Backend & FP Services

Keep large Scala backends and FP codebases consistent and easy to review.

  • Standardize style across Akka, ZIO, Cats Effect, or Play projects.
  • Clean up code before opening pull requests or sharing examples.
  • Normalize format after big refactors or library migrations.
object A{def main(args:Array[String]){println("hi")}}

object A {
  def main(args: Array[String]): Unit = {
    println("hi")
  }
}

Scala Learning & Teaching

Focus on functional concepts and types instead of spacing wars.

  • Auto-format student submissions before reviewing logic and patterns.
  • Show before/after formatting examples when teaching Scala style.
  • Prepare clean code snippets for slides, docs and blog posts.

Build & Tooling Scripts

Keep `.sbt` build files and small Scala scripts tidy.

  • Format sbt settings and dependency blocks for easier maintenance.
  • Clean helper scripts used for migrations or internal tools.

❓ Frequently Asked Questions

❓What is scalafmt and how does this tool relate to it?

Scalafmt is the standard code formatter for Scala. This online formatter aims to follow scalafmt-style behavior so that the layout you see here is close to what you get when you run scalafmt or sbt-scalafmt in your own project.

🔧Can I customize all scalafmt rules here?

This tool focuses on a sensible, opinionated profile instead of exposing every scalafmt knob. For full control, create a `.scalafmt.conf` file in your project and run scalafmt via sbt or your IDE.

🌐Does it support Scala 3 syntax?

Yes. The formatter is designed to handle modern Scala 3 features such as enums, given/using, extension methods, and more, alongside classic Scala 2 code.

🔒Is my Scala code sent to a public server?

Your code is sent over HTTPS to a private formatting backend dedicated to this tool and is not shared or indexed. For highly confidential or proprietary code, you can run scalafmt locally instead.

⚙️Will formatting change how my Scala program behaves?

The formatter is designed to change only whitespace and layout, not semantics. That said, as with any large formatting change, it is good practice to run your test suite afterwards.

Pro Tips

Best Practice

Keep a `.scalafmt.conf` file in your repo so your editor, CI and `sbt scalafmt` all use the same style.

Best Practice

Run a dedicated "format only" commit before refactors so later diffs focus on real code changes, not whitespace.

Best Practice

Use a consistent max line width across your team to avoid noisy diffs and conflicting styles.

Best Practice

When teaching, show messy Scala first, then the formatted version to highlight how layout improves readability.

Additional Resources

Scalafmt GitHub Repository
Documentation
Scala Language Documentation
Documentation
Scala Style Guide
Documentation

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