Google is coming with the new set of api with Google Now card,Api was released some time before in January this year. Check below url for more information on this.
Google Plans To Release Open API For Google Now Cards
At South by Southwest, Aparna Chennapragada, Director of Product Management for Google Now offered a glimpse into the future of the feature which has become the heart of the search experience on Android. According to Chennapragada, the company plans to have a full API for Google Now cards ready soon. This will expand on the previously announced pilot program consisting of apps like Pandora, Lyft, and others.
Until the trial run starting in late January this year, Google Now cards were controlled exclusively by Google itself.