# Date/time formatting

iSHARE adopts internationally recognised standards for expressing dates and times:

* **UTC (Coordinated Universal Time)** – Time standard unaffected by time zones or daylight saving time.
* **Unix Timestamp** – The number of seconds elapsed since the Unix epoch (1970-01-01T00:00:00Z, UTC).
  * *Example:* `1536089675` represents **2018-09-04T19:34:35Z**.
* **RFC3339 /** **ISO 8601 Date-Time Format** – A human-readable and machine-parseable representation of date and time in UTC, using the Z suffix (as defined in [ISO 8601](https://www.iso.org/iso-8601-date-and-time-format.html) and [RFC 3339](https://www.rfc-editor.org/rfc/rfc3339.html)).
  * *Example:* `2025-09-22T14:05:30.123Z`.

**Requirement**\
All date-time values **MUST** be expressed in UTC and **MUST** follow the ISO 8601 extended date-time format with milliseconds, and the `Z` UTC indicator, e.g. `YYYY-MM-DDTHH:MM:SS.sssZ`.

Unless explicitly specified, ISO8601 date-time in UTC is the default format. An exception is, for example, the [iSHARE JWT](https://dev.ishare.eu/reference/ishare-jwt), which specifies the use of a Unix Timestamp (in line with the JWT standard).