Optional speedup extension#


charset-normalizer will always remain pure Python, meaning that a environment without any build capabilities will run this program without any additional requirements.

Nonetheless, starting from the version 3.0 we introduce and publish some platform specific wheels including a pre-built extension.

Most of the time is spent in the module md.py so we decided to “compile it” using Mypyc.

  1. It does not require to have a separate code base

  2. Our project code base is rather simple and lightweight

  3. Mypyc is robust enough today

  4. Four times faster!


If your platform and/or architecture is not served by this swift optimization you may compile it easily yourself. Following those instructions (provided you have the necessary toolchain installed):

pip install mypy build wheel
pip install charset-normalizer --no-binary :all:

How not to?#

You may install charset-normalizer without the speedups by directly using the universal wheel (most likely hosted on PyPI or any valid mirror you use) with --no-binary.

E.g. when installing requests and you don’t want to use the charset-normalizer speedups, you can do:

pip install requests --no-binary charset-normalizer

When installing charset-normalizer by itself, you can also pass :all: as the specifier to --no-binary.

pip install charset-normalizer --no-binary :all: