I want to show an animation of:
- Questions being asked and answered in the most popular tag
- Comments being posted
- New users joining
All in real time.
Is there access to real-time data?
You can get data close-enough to "real time" for most practical purposes. See the StackHose app, for example.
Read the page about the API's Throttles and Quotas. From that page we can deduce:
The API developer confirms that that is about as "real time" as the API is ever going to get ("Status by design"). The API seems to be designed around reasonable request rates and volumes of traffic.
Note that that 60-second caching does not currently apply in all cases, like the