Basic properties

When an item is created, it is assigned an ID and creation time.

Item IDs

A unique identifier (ID) is assigned to each item at the time of its creation. The ID values do not indicate the order in which entities were created.

ID fields are strings, not integers.

ID uniqueness

Item IDs are unique across workspaces in a shared space and a given entity type. For example, feature IDs are unique, but a feature and test may have the same ID.
Item IDs are also unique among subtypes of the same aggregated type. For example: user stories and defects are subtypes of the same work_items aggregated type, so IDs are unique across all subtypes of work_items.
User IDs are unique in a workspace. For uniqueness across a shared space, workspace user IDs are combined with the workspace ID.

Creation time

The creation date is the date on which the item was created. In cases where the item was added through synchronization, the creation time is later than when the corresponding item was created in the originating system.