All representations of dates are strings in ISO 8601 format.
You can provide date strings that are either UTC (for example, 2019-01-01T13:25:00Z) or offset from UTC to indicate time zone (for example, 2019-01-01T23:25:00+10:00 for AEST - ten hours ahead of UTC).
Note
Regardless of the format that valid dates are provided in, all dates are standardised and stored by Afterpay in UTC. This convention is reflected in the formatting of all API responses.