Efficient Polling with the Changes-Since Parameter#

You can poll for the status of certain operations by issuing a GET request on various elements. Rather than re-downloading and re-parsing the full status at each polling interval, you can use the changes-since parameter to check for changes since a previous request. The changes-since time is specified as an ISO 8601 dateTime (2011-01-24T17:08Z).

The operations that use the changes-since filter are:

  • GET /servers

  • GET /servers/detail

  • GET /images

  • GET /images/detail

The format for the timestamp is:


Optionally, to return the time zone as an offset from UTC, append the following:


If you omit the time zone (2011-01-24T17:08), the UTC time zone is assumed.

If data has changed, only the items changed since the specified time are returned in the response.

If date has not changed since the changes-since time, an empty list is returned.

For example, issue a GET request against the following endpoint to list all servers that have changed since Mon, 24 Jan 2011 17:08:00 UTC:


To enable you to keep track of changes, the changes-since filter also displays images and servers that have been deleted provided that the changes-since filter specifies a date in the last 30 days. Items deleted more than 30 days ago might be returned, but it is not guaranteed.