For single invocations, there is the htmlmin.minify method. It takes input html as a string for its first argument and returns minified html. It accepts multiple different options that allow you to tune the amount of minification being done, with the defaults being the safest available options:

>>> import htmlmin
>>> input_html = '''
  <body   style="background-color: tomato;">
    <h1>  htmlmin   rocks</h1>
      and rolls
>>> htmlmin.minify(input_html)
u' <body style="background-color: tomato;"> <h1> htmlmin rocks</h1> <pre>\n        and rolls\n      </pre> </body>'
>>> print htmlmin.minify(input_html)
 <body style="background-color: tomato;"> <h1> htmlmin rocks</h1> <pre>
        and rolls
      </pre> </body>

If there is a chunk of html which you do not want minified, put a pre attribute on an HTML tag that wraps it. htmlmin will leave the contents of the tag alone and will remove the pre attribute before it is output:

>>> import htmlmin
>>> input_html = '''<span>   minified   </span><span pre>   not minified   </span>'''
>>> htmlmin.minify(input_html)
u'<span> minified </span><span>   not minified   </span>'

Attributes will be condensed to their smallest possible representation by default. You can prefix an individual attribute with pre- to leave it unchanged:

>>> import htmlmin
>>> input_html = '''<input value="&lt;minified&gt;" /><input pre-value="&lt;not minified&gt;" />'''
>>> htmlmin.minify(input_html)
u'<input value="<minified>"><input value=&lt;not minified&gt;>'

The minify function works well for one off minifications. However, if you are going to minify several pieces of HTML, the Minifier class is provided. It works similarly, but allows for persistence of options between invocations and recycles the internal data structures used for minification.

Command Line

htmlmin is invoked by running:

htmlmin input.html output.html

If no output file is specified, it will print to stdout. If no input specified, it reads form stdin. Help with options can be retrieved at any time by running htmlmin -h:

htmlmin -h
usage: htmlmin [-h] [-c] [-s] [--remove-all-empty-space]
               [--keep-optional-attribute-quotes] [-H] [-k] [-a PRE_ATTR]
               [-p [TAG [TAG ...]]] [-e ENCODING]
               [INPUT] [OUTPUT]

Minify HTML

positional arguments:
  INPUT                 File path to html file to minify. Defaults to stdin.
  OUTPUT                File path to output to. Defaults to stdout.

optional arguments:
  -h, --help            show this help message and exit
  -c, --remove-comments
                        When set, comments will be removed. They can be kept on an individual basis
                        by starting them with a '!': <!--! comment -->. The '!' will be removed from
                        the final output. If you want a '!' as the leading character of your comment,
                        put two of them: <!--!! comment -->.

  -s, --remove-empty-space
                        When set, this removes empty space betwen tags in certain cases.
                        Specifically, it will remove empty space if and only if there a newline
                        character occurs within the space. Thus, code like
                        '<span>x</span> <span>y</span>' will be left alone, but code such as
                        '   ...
                        will become '...</head><body>...'. Note that this CAN break your
                        html if you spread two inline tags over two lines. Use with caution.

                        When set, this removes ALL empty space betwen tags. WARNING: this can and
                        likely will cause unintended consequences. For instance, '<i>X</i> <i>Y</i>'
                        will become '<i>X</i><i>Y</i>'. Putting whitespace along with other text will
                        avoid this problem. Only use if you are confident in the result. Whitespace is
                        not removed from inside of tags, thus '<span> </span>' will be left alone.

                        When set, this keeps all attribute quotes, even if they are optional.

  -H, --in-head         If you are parsing only a fragment of HTML, and the fragment occurs in the
                        head of the document, setting this will remove some extra whitespace.

  -k, --keep-pre-attr   HTMLMin supports the propietary attribute 'pre' that can be added to elements
                        to prevent minification. This attribute is removed by default. Set this flag to
                        keep the 'pre' attributes in place.

  -a PRE_ATTR, --pre-attr PRE_ATTR
                        The attribute htmlmin looks for to find blocks of HTML that it should not
                        minify. This attribute will be removed from the HTML unless '-k' is
                        specified. Defaults to 'pre'. You can also prefix individual tag attributes
                        with ``{pre_attr}-`` to prevent the contents of the individual attribute from
                        being changed.

  -p [TAG [TAG ...]], --pre-tags [TAG [TAG ...]]
                        By default, the contents of 'pre', and 'textarea' tags are left unminified.
                        You can specify different tags using the --pre-tags option. 'script' and 'style'
                        tags are always left unmininfied.

  -e ENCODING, --encoding ENCODING
                        Encoding to read and write with. Default 'utf-8'.