I am seeking a reliable **REST API** that can provide **world time and time zone information across platforms**.

I need the current time as a string. I'd like it to **return the result in under a second**, regardless of the user's location worldwide. 

Among other implementations I want to use this for a consistent countdown timer, to be more accurate than a user's [possibly-inaccurate] computer time. It can be GMT or another time zone, as long as the time zone and offset is specified, like `2012-11-05 16:16:50 EST`.

I would build this API myself, but have concerns of **potential latency issues** (as well as inelegance) when filtering someone through a whole big software stack like Rails just to return a simple `String`. 

Excessive latency for users far away from the US east coast would offset the benefit of accuracy that the task requires. 

Any suggestions and/or examples are appreciated.