⌘ K
python · whitespace · normalise · live

Clean up Python whitespace

Normalises tabs/spaces, trims trailing whitespace, collapses blank-line runs, and tidies comment + comma spacing. Use black or ruff format for real formatting. Runs locally.

Python Formatter
Input
48 B
3 lines
Output
50 B
4 lines
Status
ready
live
Ratio
1.04×
out/in
input · python
output · cleaned python
def add(a, b ):
    return a+b
print( add(1, 2 ))
Quick Start

How to clean Python

Python is whitespace-significant, so we never re-indent. We just normalise tabs, blank-line runs, and trailing whitespace.

  1. 01

    Paste source

    Any .py file — script, module, or a short snippet from REPL.

    Parsing runs through Prettier’s standalone bundle (or the language-specific equivalent) loaded lazily — no parser ships until the tool is opened.

    pythonPrettierASTstandalonelazy
    input · sourceraw · AST
    def f(a,b ):
  return a+b
    loaded · parsedAST · ready
  2. 02

    Set indent width

    4 spaces is the PEP 8 default. Tabs in the input are expanded to this many spaces.

    Indent width, tab style, and print-width re-format through a memoised pass — switching 2 → 4 spaces never re-parses, only re-prints.

    optionsindentprint-widthmemoisedlive
    opts · optionsindent · live
    indent=4
    options applied · livelive
  3. 03

    Watch whitespace clean up

    Trailing spaces are stripped, 3+ blank lines become 2, # becomes "# ", and ", " spacing is normalised on simple lines.

    The formatter is deterministic and idempotent: running it twice produces byte-identical output, which keeps diffs and git noise to a minimum.

    liveidempotentdeterministicdiff-cleanstable
    out · formattedtidy · ready
    def f(a, b):
    return a + b
    formatted · liveidempotent
  4. 04

    Copy or download

    Save as .py or copy to clipboard. Source stays in your browser.

    Download writes a Blob with the language-appropriate extension; copy uses navigator.clipboard.writeText so the output preserves all whitespace exactly.

    exportclipboardbloblanguage MIMEclient-side
    ok · copiedready · done
    OK Copied
    shipped · ready to shipsuccess
Pro tips

Formatting tips that keep diffs sane

Pick one config and pin it

Inconsistent formatting causes diff churn. Commit .prettierrc / .editorconfig and enforce in CI.

Format on save

Editor integration is faster feedback than a pre-commit hook. Use both for belt-and-braces.

Idempotency matters

Running the formatter twice should produce identical output. Test this on a representative file.

Match the language community

Default to community conventions: 2 spaces for JS/CSS, 4 for Python, tabs for Go. Fights over indent are a productivity tax.

Print-width drives wrapping

80, 100, and 120 are the common targets. Wider lines parse fast but review slower side-by-side.

Don’t mix formatters and linters

Prettier handles whitespace; ESLint handles correctness. Disable overlapping rules to avoid fight-club configs.

Related toolsRuby FormatterJavaScript FormatterYAML FormatterTOML FormatterJSON FormatterSort Imports
Use Cases

When to clean Python whitespace

Snippet cleanup, code reviews, lint-pass prep.

Snippet cleanup

Tidy a tutorial paste before running it. Idempotent: running the formatter twice produces byte-identical output, which is the foundation of a clean CI gate. Pair with a pre-commit hook so PRs arrive already formatted, focusing review on logic.

idempotent

Code reviews

Strip whitespace churn so diffs show real changes. Pairs with EditorConfig + .prettierrc for end-to-end consistency. Whitespace-only changes vanish so reviewers see real diffs, and git blame stays honest about who wrote what.

CI-ready

Tab/space audit

Find and normalise mixed indentation. Output respects your indent width, tab style, and print-width — settings carry over for repeat runs. Switching 2-space to 4-space costs nothing in CPU but standardises an entire codebase.

diff-clean

Pre-black

Quick clean before running black or ruff locally. Format-on-save is the fastest feedback loop; CI is the safety net. Together they make inconsistent indentation a thing of the past and free up review cycles for genuine concerns.

PR-friendly

Notebook export

Tidy a .py file exported from a Jupyter notebook. Whitespace-only changes don't trigger downstream content-hash invalidations, so CDN cache keys and CI cache layers stay warm. Real changes get all the rebuild budget.

review-ready

Docs examples

Standardise Python examples for documentation. Pairs with linters (ESLint, Stylelint, pylint) that catch what formatting alone can't — bugs, unused imports, dead code. Each tool stays in its lane, and the codebase stays clean.

deterministic
FAQ

Frequently asked questions

No — black is an AST-aware formatter. This tool only handles whitespace cleanup which is safe in the browser.
Leading whitespace is rounded to the nearest multiple of indent. Mixed-indent files may shift; back them up first.
Comma and operator spacing fixes use simple regex — they may rewrite , inside strings. Inspect output before saving.
Type hints live on the same line as their declarations and are preserved verbatim.
No — the formatter runs locally in your browser tab.
Suggest a tool

Something missing?

Tell us what you need. We ship the top requests every two weeks.

Sent straight to the maintainers · no account needed
47 in queue·8 shipped this month
Request queued. Thanks!