To implement Facebook login using Ory, you need to configure Facebook as a social sign-in provider and handle the OAuth2 flow. Here's a brief overview of how to work with Facebook login and access tokens in Ory: 1. First, you need to set up Facebook as a social sign-in provider in your Ory project. This involves creating a Facebook Developer account and configuring the Facebook app. You can find detailed instructions on how to do this in the [Facebook Social Sign-In documentation](https://www.ory.sh/docs/kratos/social-signin/facebook). 2. When configuring Facebook as a provider, you'll need to add the

email

scope to request access to the user's email address. This is done in the Ory configuration:

yaml selfservice:   methods:     oidc:       config:         providers:           - id: facebook             provider: facebook             client_id: ....             client_secret: ....             mapper_url: "base64://{YOUR_BASE64_ENCODED_JSONNET_HERE}"             scope:               - email

3. Facebook only returns an

access_token

and doesn't return an

id_token

. Ory handles this by sending requests to Facebook's Graph API to retrieve user information and adds it to

std.extVar('claims')

for use in data mapping. 4. In your application, you'll need to implement the OAuth2 Authorization Code flow to obtain the access token. The [OAuth2 Authorization Code Flow documentation](https://www.ory.sh/docs/oauth2-oidc/authorization-code-flow) provides details on how to implement this flow. 5. Once you have the access token, you can use it to make requests to Facebook's APIs on behalf of the user. However, it's important to note that this access token is meant for use with Facebook's APIs, not directly with Ory's APIs. Remember that OAuth2 scopes are not permissions. As stated in the [OAuth2 concepts documentation](https://www.ory.sh/oauth2-openid-connect-do-you-need-use-cases-examples/#scopes-are-not-permissions), "The OAuth2 scope does not say what a user can and cannot do." The access token represents that the client application has been authorized by the user to access certain resources on their behalf. For secure handling of tokens and implementing the full OAuth2 flow, it's recommended to follow best practices and use well-tested libraries that support the OAuth2 and OpenID Connect protocols.