What exactly does the T and Z mean in timestamp?

I have this timestamp value being return by a web service "2014-09-12T19:34:29Z"

I know that it means timezone, but what exactly does it mean?

And I am trying to mock this web service, so is there a way to generate this timestamp using strftime in python?

Sorry if this is painfully obvious, but Google was not very helpful and neither was the strftime() reference page.

I am currently using this :

x.strftime("%Y-%m-%dT%H:%M:%S%Z")'2015-03-26T10:58:51'