REST API for authentication with Cognito User Pool

Amazon Cognito provides InitiateAuth API which you can use for a client-side authentication flow like the example provided in the link you noted. However, please note that you can't sign in a user with a federated IdP with InitiateAuth. If you are looking to do a server-side authentication flow, take a look at AdminInitiateAuth. For further details, please take a look at Cognito authentication/user pool authentication flow documentation. An AWS CLI command example for InitiateAuth can be found here.

• InitiateAuth
• AdminInitiateAuth