curl -X POST --data @aws-auth-data.json
-H 'X-Amz-Target: AWSCognitoIdentityProviderService.InitiateAuth'
-H 'Content-Type: application/x-amz-json-1.1'
https://cognito-idp.us-east-1.amazonaws.com/

{
   "AuthParameters" : {
      "USERNAME" : "yourusername@example.com",
      "PASSWORD" : "yourpassword"
   },
   "AuthFlow" : "USER_PASSWORD_AUTH",
   "ClientId" : "75........................"
}