rcssmin

library1.2.2pypypi✓ verified 25d ago

RCSSmin is a CSS minifier written in Python, based on the semantics of the YUI compressor. It prioritizes speed over maximum compression, performing syntactical compression only by removing spaces, comments, and semicolons, while supporting various CSS hacks. It includes a C re-implementation (`rcssmin.c`) that significantly improves runtime performance. The current version is 1.2.2.

devops

pip install rcssmin

package ↗homepage ↗

INSTALL

IMPORT

SIG · RCSSMIN

rcssmin

devopspythonv1.2.2

Install

1.6s avg

Import

—

Disk

16MB

Pass rate

10/ 10

Env Coverage10 / 10

glibc

3.9–3.13

musl

3.9–3.13

Install & Compatibility

Where this runs

tested against v1.2.2 · pip install

no network on importno background threads

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

py 3.10–3.95 runs

installs and imports cleanly · install 0.0s · import 0.000s · 17.9MB

glibc

py 3.10–3.95 runs

installs and imports cleanly · install 1.6s · import 0.000s · 18MB

16MB installed

● package 16MB

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

cssmin

✓ from rcssmin import cssmin

The primary function for minifying CSS.

This example demonstrates basic CSS minification and how to optionally preserve 'bang comments' (comments starting with `!`).

import rcssmin css_input = """\ /* This is a comment */ body { color: #fff; /* inline comment */ font-size: 16px; /*! Important comment */ } .container { margin: 0 auto; } """ # Basic minification minified_css = rcssmin.cssmin(css_input) print(f"Basic Minified:\n{minified_css}") # Expected: body{color:#fff;font-size:16px}.container{margin:0 auto} # Keep 'bang comments' (comments starting with !) minified_with_bang = rcssmin.cssmin(css_input, keep_bang_comments=True) print(f"\nMinified with Bang Comments:\n{minified_with_bang}") # Expected: body{color:#fff;font-size:16px/*! Important comment */}.container{margin:0 auto}

rcssmin --version

Debug

Known issues

gotchaInstalling `rcssmin` on Windows (and some other platforms) might require a C compiler (e.g., Visual C++ Build Tools) to build its faster C extension (`rcssmin.c`). Without a compiler, the installation might fall back to the slower pure Python implementation, or fail entirely if not properly handled by `pip`.

fix

Ensure a C compiler is available on the system, or manually force the pure Python installation if performance is not critical (e.g., `pip install --no-binary :all: rcssmin`).

affects: All versions with C extension (since 1.0.0).

gotcha`rcssmin` performs only *syntactical* CSS compression (e.g., stripping spaces, comments, semicolons). It does not perform *semantic* compression, such as removing empty CSS blocks, collapsing redundant properties, or short-handing properties. Users expecting deeper optimization should consider other tools or combine `rcssmin` with a semantic optimizer.

fix

Understand `rcssmin`'s scope; for semantic optimization, integrate other tools into your build pipeline.

affects: All versions

gotchaBy default, `rcssmin.cssmin` removes all comments. To preserve 'bang comments' (comments starting with an exclamation mark, e.g., `/*! License */`), you must explicitly set the `keep_bang_comments=True` parameter.

fix

Pass `keep_bang_comments=True` to the `cssmin` function to retain desired comments.

affects: All versions

gotchaWhile older versions of `rcssmin` and its documentation might mention Python 2.7 support, the library is primarily developed and tested for Python 3.6+. Recent distribution packages have also dropped Python 2 support. For reliable and performant operation, use Python 3.6 or newer.

fix

Ensure your project uses Python 3.6 or a later version for compatibility and optimal performance.

affects: < 1.0.6 (Python 2.7, 3.6+); >= 1.0.6 (Python 3.6+ recommended)

Errors

Common errors & fixes

ModuleNotFoundError: No module named 'rcssmin'

The rcssmin package is not installed in the current Python environment.

fix

pip install rcssmin

TypeError: argument of type 'int' is not iterable

The rcssmin.cssmin() function expects a string containing CSS code as input, but received an incompatible type.

fix

Ensure the input to rcssmin.cssmin() is a string, for example: rcssmin.cssmin('body { color: red; }')

AttributeError: module 'rcssmin' has no attribute 'minify_css'

The user attempted to call a non-existent method; the correct function for minifying CSS is cssmin.

fix

Use rcssmin.cssmin() instead of rcssmin.minify_css().

Upgrade

Version history

1.2.2latest on PyPI · released Oct 12, 2025

Audit

Dependencies

pythonrequiredRuntime dependency for the Python implementation.

setuptoolsrequiredCommon build-time dependency for Python packages, especially those with C extensions.

C compileroptionalRequired for compiling the faster C extension (rcssmin.c) during installation. If unavailable, the slower Python implementation is used.

Agent activity

14 hits · last 30 days

node

Resources

packagehttps://pypi.org/project/rcssmin/ ↗

homepagehttps://opensource.perlig.de/rcssmin/ ↗