Certifi provides Mozilla's carefully curated collection of Root Certificates for validating the trustworthiness of SSL certificates while verifying the identity of TLS hosts. It has been extracted from the Requests project.

certifi is available on PyPI. Simply install it with pip:

$ pip install certifi

To reference the installed certificate authority (CA) bundle, you can use the built-in function:

>>> import certifi

>>> certifi.where()
'/usr/local/lib/python3.7/site-packages/certifi/cacert.pem'

Or from the command line:

$ python -m certifi
/usr/local/lib/python3.7/site-packages/certifi/cacert.pem

Enjoy!

Browsers and certificate authorities have concluded that 1024-bit keys are unacceptably weak for certificates, particularly root certificates. For this reason, Mozilla has removed any weak (i.e. 1024-bit key) certificate from its bundle, replacing it with an equivalent strong (i.e. 2048-bit or greater key) certificate from the same CA. Because Mozilla removed these certificates from its bundle, certifi removed them as well.

In previous versions, certifi provided the certifi.old_where() function to intentionally re-add the 1024-bit roots back into your bundle. This was not recommended in production and therefore was removed at the end of 2018.

Certifi does not support any addition/removal or other modification of the CA trust store content. This project is intended to provide a reliable and highly portable root of trust to python deployments. Look to upstream projects for methods to use alternate trust.