All resources returned by Payable have a set of timestamps attached.
You will see the properties created_at and updated_at. The created timestamp is the datetime that the resources was created. The updated timestamp is the datetime of the last update to that resources.
These timestamps are ISO 8601 standard. For example - August 9, 2022 at 12:15:48 UTC would be represented as 2022-08-09T12:15:48.2769526Z.