title: AWS Cognito, Lambda, User credentials in DynamoDB
body: <p>I established a authentication flow with Facebook Login and AWS Cognito on the client site. Works fine. But now I need a reference of the user with its facebook id in a dynambodb table. Of course I could just call a AWS lambda function exposed via AWS API gateway, but how can I verify that the API call actually has a valid facebook id and that this facebook id matches the AWS Cognito Id. Maybe I am missing something here, I hope you guys can point me in the right direction ;) thanks! </p>