A Flask-Dance blueprint has a backend associated with it, which is simply an object that knows how to store and retrieve OAuth tokens from some kind of persistent storage. The default storage backend uses the Flask session to store OAuth tokens, which is simple and requires no configuration. However, when the user closes their browser, the OAuth token will be lost, so its not a good choice for production usage. Fortunately, Flask-Dance comes with some other backends to choose from.


SQLAlchemy is the “standard” ORM for Flask applications, and Flask-Dance has great support for it. First, define your database model with a token column and a provider column. Flask-Dance includes a OAuthConsumerMixin class to make this easier:

from flask_sqlalchemy import SQLAlchemy
from flask_dance.consumer.backend.sqla import OAuthConsumerMixin

db = SQLAlchemy()
class OAuth(OAuthConsumerMixin, db.Model):

Next, create an instance of the SQLAlchemy backend and assign it to your blueprint:

from flask_dance.consumer.backend.sqla import SQLAlchemyBackend

blueprint.backend = SQLAlchemyBackend(OAuth, db.session)

And that’s all you need – if you don’t have user accounts in your application. If you do, it’s slightly more complicated:

from flask_sqlalchemy import SQLAlchemy
from flask_login import current_user
from flask_dance.consumer.backend.sqla import OAuthConsumerMixin, SQLAlchemyBackend

db = SQLAlchemy()

class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    # ... other columns as needed

class OAuth(OAuthConsumerMixin, db.Model):
    user_id = db.Column(db.Integer, db.ForeignKey(
    user = db.relationship(User)

blueprint.backend = SQLAlchemyBackend(OAuth, db.session, user=current_user)

There are two things to notice here. One, the model that you use for storing OAuth tokens must have a user relationship to the user that it is associated with. Two, you must pass a reference to the currently logged-in user (if any) to SQLAlchemyStorage. If you’re using Flask-Login, the current_user proxy works great, but you could instead pass a function that returns the current user, if you want.

You also probably want to use a caching system for your database, so that it is more performant under heavy load. The SQLAlchemy token storage backend also integrates with Flask-Caching if you just pass an Flask-Caching instance to the backend, like this:

from flask import Flask
from flask_caching import Cache

app = Flask(__name__)
cache = Cache(app)

# setup Flask-Dance with SQLAlchemy models...

blueprint.backend = SQLAlchemyBackend(OAuth, db.session, cache=cache)


Of course, you don’t have to use SQLAlchemy, you’re free to use whatever storage system you want. Writing a custom backend is easy: just subclass flask_dance.consumer.backend.BaseBackend and override the get, set, and delete methods. For example, here’s a backend that uses a file on disk:

import os
import os.path
import json
from flask_dance.consumer.backend import BaseBackend

class FileBackend(BaseBackend):
    def __init__(self, filepath):
        super(FileBackend, self).__init__()
        self.filepath = filepath

    def get(self, blueprint):
        if not os.path.exists(self.filepath):
            return None
        with open(self.filepath) as f:
            return json.load(f)

    def set(self, blueprint, token):
        with open(self.filepath, "w") as f:
            json.dump(token, f)

    def delete(self, blueprint):

Then, just create an instance of your backend and assign it to the backend attribute of your blueprint, and Flask-Dance will use it.