ISO 8601 is the International Standard for the representation of dates and times. It is recommended to use the ISO-8601 format for representing the date and time in your RESTful web APIs. Here is an example for the ISO-8601 date and time: YYYY-MM-DDThh:mm:ss.sTZD (for example, 2015-06-16T11:20:30.45+01:00)

The API that you build must be capable of accepting any time zone set by the client.

While storing the date and time fields present in the resource representation in the database, use Coordinated Universal Time (UTC). UTC is guaranteed to be consistent.

While retuning the date and time fields in response to an API call, use the UTC time zone. The client can easily convert the date field present in the resource into the desired local time by using an appropriate UTC offset.