certifi

Python package for providing Mozilla's CA Bundle.

certifi Copyleft license MPL-2.0 Active ★ 988 v2026.7.22 released 2026-07-22

Install

certifi on PyPI

pip

pip install certifi

uv

uv add certifi

poetry

poetry add certifi

Package facts

License	MPL-2.0 (copyleft)
Python support	supports the current Python release (>=3.7)
Install friction	low — pure-Python wheel
Runtime dependencies	none
Maintenance	actively maintained — 22 days since the last release
Last repo commit	2026-08-03
First released	2011-12-28
Popularity	one of the 100 most-downloaded packages on PyPI (30-day window, as of 2026-08-13)
Known vulnerabilities	none known (OSV.dev, checked 2026-08-13)

Evidence: certifi-2026.7.22-py3-none-any.whl

Development Status :: 5 - Production/StableIntended Audience :: DevelopersLicense :: OSI Approved :: Mozilla Public License 2.0 (MPL 2.0)Natural Language :: EnglishProgramming Language :: PythonProgramming Language :: Python :: 3Programming Language :: Python :: 3 :: OnlyProgramming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Programming Language :: Python :: 3.14Programming Language :: Python :: 3.7Programming Language :: Python :: 3.8Programming Language :: Python :: 3.9

About certifi

from the package's own PyPI description — quoted content, verbatim

Certifi: Python SSL Certificates

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.

Installation

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

$ pip install certifi

Usage

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

&gt;&gt;&gt; import certifi

&gt;&gt;&gt; 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!

.. _Requests: https://requests.readthedocs.io/en/latest/

Addition/Removal of Certificates

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.

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AI interpretation — verify before relying

AI-generated interpretation of the package facts above; every digit, version, license, or vulnerability id it cites is grounded in the facts already shown on this page

Certifi provides Mozilla's curated collection of Root Certificates for validating SSL/TLS certificate trustworthiness and host identity in Python applications.

Low install friction with no runtime dependencies. Actively maintained with a recent release (22 days old) and steady repository activity.

Licensed under MPL-2.0 (copyleft), which requires source code disclosure of modifications but permits proprietary use of the package itself in most contexts.

Usage

import certifi

# Get path to the CA bundle
ca_bundle_path = certifi.where()
print(ca_bundle_path)

Requires Python 3.7 or later.

Verdict: Certifi is a stable, widely-used foundation for SSL/TLS certificate validation with zero security vulnerabilities, active maintenance, and minimal installation overhead. The MPL-2.0 copyleft license is permissive for most use cases but requires attention if you modify the package itself.

Needs verification

Whether the CA bundle is automatically updated on package upgrades or requires manual intervention.
Performance implications of certificate validation in high-throughput scenarios.

ssl certificate validationroot ca bundle pythontls certificate authoritymozilla ca certificatespython ssl certificatescertificate verificationtrusted ca store