We're currently working on a new streaming API that is faster and more scalable. The API is currently in a closed alpha stage. Unfortunately there is no timeframe on when we'll be able to release it to the public.
We will prioritise market makers when issuing streaming API accounts. If you would like to gain alpha access to this service, you can apply by outlining your proposal here.
Odds Feeds (public)
The feed is updated every few seconds but the information is delayed by 30 seconds.
If you have questions or comments regarding the odds feed please contact us at firstname.lastname@example.org.