TLS with SNI-support for Python 2. Follow these instructions if you would like to verify TLS certificates in Python 2. Note, the default libraries do not do certificate checking; you need to do additional work to validate certificates yourself.

This needs the following packages installed:

However, pyopenssl depends on cryptography, which depends on idna, so while we use all three directly here we end up having relatively few packages required.

You can install them with the following command:

$ python -m pip install pyopenssl cryptography idna

To activate certificate checking, call inject_into_urllib3() from your Python code before you begin making HTTP requests. This can be done in a sitecustomize module, or at any other time before your application begins using urllib3, like this:

    import urllib3.contrib.pyopenssl
except ImportError:

Now you can use urllib3 as you normally would, and it will support SNI when the required modules are installed.

Activating this module also has the positive side effect of disabling SSL/TLS compression in Python 2 (see CRIME attack).


Undo monkey-patching by inject_into_urllib3().


Monkey-patch urllib3 with PyOpenSSL-backed SSL-support.