1) Currently we can trigger the content export to file on link like this:
http://arturyc.ezstudiodemo.com/api/ezp/v2/ez_recommendation/v1/contenttypes/16,18,38/export?hidden=1&fields=title,name&page_size=1000

2) After the export is ready, eZ triggers yoochoose api on www.admin.yoochoose.net/api/

/items - this link is hard coded in eZ bundle and we would want it to be parameter in the link from point 1) so it would look like :
http://arturyc.ezstudiodemo.com/api/ezp/v2/ez_recommendation/v1/contenttypes/16,18,38/export?hidden=1&fields=title,name&page_size=1000&webHook=http%3A%2F%2Fadmin.yoochoose.net%2Fapi%2F<mandatorId>%2Fitems&transaction=2016110341234

It is also described here:
https://doc.yoochoose.net/display/PUBDOC/Import+V2

Example with an eZ installation:
1) YC to EZ:
GET: http://ezstudio.yoochoose.net:8000/api/ezp/v2/ez_recommendation/v1/contenttypes/2/export?hidden=1&lang=eng-GB&fields=title,intro,body&webHook=https%3A%2F%2Fadmin.test.yoochoose.net%2Fapi%2F723%2Fitems&transaction=20170104084311232

2) EZ to YC after finishing the export
POST: https://admin.yoochoose.net/api/723/items
BODY:

{
   "transaction":"2016110341234",
   "events":[
      {
         "action":"FULL",
         "format":"EZ",
         "contentTypeId":2,
         "lang":"eng-GB",
         "uri":[
            "http:\/\/ezstudio.yoochoose.net:8000\/api\/ezp\/v2\/ez_recommendation\/v1\/exportDownload\/2017\/01\/04\/10\/14\/20"
         ],
         "credentials":{
            "login":"yc",
            "password":"c5dd518251"
         }
      }
   ]
}