What real time APIs are there that don't require polling, for things like bus locations, flight locations, etc... -- which I can just poll with a web socket?
ProgrammableWeb(.com) is a great resource about APIs and includes an API directory. A direct link for searching APIs in their catalog that mention
websocket is http://www.programmableweb.com/category/all/apis?keyword=websocket . There is also a "real time API" category at http://www.programmableweb.com/category/real-time/api. Some may qualify as "open data".
I also stumbled upon http://streamdata.io/ which advertises that it is a solution to take a REST API and turn it into a streaming one. Two APIs that I know of that are updated on several-times-a-day basis are as follows. You could construct an API call that
- https://data.colorado.gov/Water/DWR-Current-Surface-Water-Conditions/4yw9-a5y6 [API call for latest results is https://data.colorado.gov/resource/a97x-8zfv.json?$limit=10000&$order=date_time%20desc]
Hope this helps some!