What works, what does not?

**Works**: tabs ↔ spaces swap, indent-width normalisation, trim trailing whitespace, line-ending normalisation (CRLF → LF), trailing newline at file end. **Does not work**: wrapping long lines, inserting new brackets/semicolons, automatic style fixes (e.g. `if x:` vs `if (x):`), import reorganisation, function sorting.

Can I be sure it will not break my code?

**Yes** - because cosmetic mode only changes **whitespace** (spaces, tabs, end-of-line). The actual code text (variables, keywords, strings) is **not touched**. If your Rust worked before beautify, it will work after. Exception: some languages (Python, YAML) are sensitive to the **exact indent width** - if you switch from 4 spaces to 2, the code still works but the **whole file** must have a consistent style.

Are there better online tools for full beautify?

For Rust **fully online** - probably not. It is simply not feasible without heavy runtimes. Best options: run locally (click Format in VS Code with the right extension), or install the formatter via npm/pip/cargo. For Rust → search the docs for the **official formatter** (usually one is community-recommended).

Is the syntax highlighting accurate?

**Yes** - we use **Shiki**, a library that loads **TextMate grammars** (the same ones VS Code uses). For Rust you get **identical** colours to those in the editor. Default theme: **github-dark**.

Rust Beautifier

Fix Rust indentation in your browser - tabs/spaces, CRLF→LF. (Full rustfmt needs the toolchain.)

LiveRuns in your browser

Language

VS Code style: Rust gets indentation fix onlyA full formatter for this language would need ~10 MB of downloads (Black via Pyodide for Python, etc). So we do what VS Code does without a registered extension: indentation, tabs, trailing whitespace - yes. Structural reformat - no.

First format loads the libraries (~1 second)

Source5 lines

Output

Click "Format" to see the output.

Rust beautifier - fix Rust indentation in your browser

Rust is a language whose full formatters (like Black for Python, gofmt for Go) do not run in a browser - they would require Pyodide / WASM / JVM weighing tens of megabytes. For Rust we therefore do VS-Code-style cosmetic formatting - the Cosmetic-only mode.

What it actually changes: tabs ↔ spaces conversion, indent-width normalisation (pick: tab / 2 / 4 spaces), trim trailing whitespace, line-ending normalisation (CRLF → LF). It does not change code structure - that would be a job for a real formatter, which for Rust you need to run locally.

Same thing Format Document in VS Code does for Rust without a registered formatter extension. Safe - will not break your code because it does not touch syntactic constructs.

After formatting you get a syntax-highlighted preview (powered by Shiki, the same TextMate grammars VS Code uses).

How to use it

Pick a mode (Gentle / Aggressive / Cosmetic-only) or keep the default.
Paste your code into the left panel, or use "Upload file".
Tune settings (gear icon): indent, width, quotes, semicolons.
Click Format - first click takes a moment (libraries lazy-load).
On the right you get the output with syntax highlighting - copy, download, or open in new tab.

When this is useful

Five situations where this is useful:

Tabs-to-spaces conversion (or vice-versa). Your `.editorconfig` says 2 spaces, a colleague's code has tabs.
CRLF → LF normalisation. A file from Windows opened on Linux - git complains.
Trim trailing whitespace. Spaces at end of lines (the classic copy from PDF / email).
Syntax-highlighted preview. You pasted Rust into an editor without colouring - beautify, get a preview.
Reformat imported code. You copied a snippet from Stack Overflow / GitHub and the indentation drifted.

Questions and answers

Because Rust formatters (when they exist) are written in languages like Rust, Go, C++ or Rust and do not run in a browser without heavy runtimes (Pyodide, WASM, JVM). All together that is 5-30 MB of download on first page load. This is a deliberate choice - we do not want to turn the tool into a 30 MB bundle. For full formatting run a local formatter (Black, gofmt, rustfmt, google-java-format, etc.).

First format loads the libraries (~1 second)

Source5 lines

Output

Click "Format" to see the output.

Rust Beautifier

Other languages

Rust beautifier - fix Rust indentation in your browser

How to use it

When this is useful

Questions and answers

Related tools

Code beautifier

JavaScript Beautifier

TypeScript Beautifier

Python Beautifier

Java Beautifier

C++ Beautifier

Go Beautifier

HTML Beautifier

Rust Beautifier

Other languages

Rust beautifier - fix Rust indentation in your browser

How to use it

When this is useful

Questions and answers

Related tools

Code beautifier

JavaScript Beautifier

TypeScript Beautifier

Python Beautifier

Java Beautifier

C++ Beautifier

Go Beautifier

HTML Beautifier