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 configuration from
app.config <flask.Flask.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
/extensiondev to develop your own Flask extension.