Although ProgrammableWeb had a smaller sample size of streaming APIs (34), their ratios matched what we see in APIhub's numbers. Over 75% of the APIs used REST, and JSON had only one more than XML. There were 20 for JSON vs 21 for XML.
When I compared the streaming APIs with the total number of APIs in APIhub, you see some differences in how these streaming APIs are being developed versus the general API pool
Here were my observations about the entire repository on APIhub:
- SOAP APIs are equal to about half of the number of REST APIs.
- More APIs use XML for the data format. About 7000 use XML while approximately 5000 use JSON.
- The numbers for other data formats and protocols don't come close to the ones already mentioned in the first two points.
It seems like the answer for REST is clearly 'yes', but I'm not so sure about XML vs. JSON. Here's a little qualitative data for you: Although streaming experts at Salesforce and DataSift use JSON (and PHP as an alternate for DataSift), Twitter uses XML. So there's no consensus among the major real-time players yet, and maybe that's because neither has the versatility to make the other obsolete.