Im Using User Pool, and is possible develop a api to communicate with AWS Cognito? or just to communicate with front-end apps (android, ios, javascript web)?
And if is possible, how can I identify the user logged and get their informations?
UPDATE 1: To get decode jwt informations: https://github.com/awslabs/aws-support-tools/tree/master/Cognito/decode-verify-jwt
UPDATE 2: Cognito is better to use on front-end, because you need store 'cognitoUser' object. And the methods is using this object.
UPDATE 3: You can do the login on backend, and use the token to use API Gateway on AWS. But the problem is if you need update something on Cognito. If you need, you can use the admin methods (https://docs.aws.amazon.com/cognito-user-identity-pools/latest/APIReference/Welcome.html).