Using Google Mini for a website that needs output from the Google Mini in a JSON/JSONP format for front-end querying purposes. Google Mini does publish an XML feed that could potentially be used by a middle process to convert to JSON/JSONP.
Can Google Search Appliance / Mini output to JSON/JSONP using a plug-in, modification to an XSLT template, or other unknown method?
Created a Google Mini frontend that generates a JSONP response.
I had the same problem trying to get JSON and JSONP. The solution worked in general on all other browsers, but IE. I could not change the mime-type to something other than text/html since that was global in GSA. Created an XSLT to solve that problem for browsers like IE which will not allow content to be returned due to a security feature ( IE – SEC7112 )
https://github.com/kjonnala/gsa_template
Hope that helps.