Once the transaction is complete, the user will be redirected to the given request URL.
If the transaction is successful, user will be redirected automatically to given success_url
If transaction gets failed, user will be redirected to the provided failure_url
In both cases, payment_id will be provided as a query parameter; hence you can use this payment_id as transaction_id to retrieve transaction details and status information from the given API.
More details about API is explained in API reference section.