Extensions are extra packages that add functionality to a Flask application. For example, an extension might add support for sending email or connecting to a database. Some extensions add entire new frameworks to help build certain types of applications, like a REST API.
Flask extensions are usually named “Flask-Foo” or “Foo-Flask”. You can search PyPI for packages tagged with Framework :: Flask.
Consult each extension’s documentation for installation, configuration,
and usage instructions. Generally, extensions pull their own
app.config and are
passed an application instance during initialization. For example,
an extension called “Flask-Foo” might be used like this:
from flask_foo import Foo foo = Foo() app = Flask(__name__) app.config.update( FOO_BAR='baz', FOO_SPAM='eggs', ) foo.init_app(app)
While the PyPI contains many Flask extensions, you may not find an extension that fits your need. If this is the case, you can create your own. Read Flask Extension Development to develop your own Flask extension.