The site of Google Custom Search Objective-C library offers a library and a framework to access the JSON APIs. It aims to be flexible to work with Google APIs for iOS and Mac OS X apps. It is compatible with iOS3+ and Mac OS X 10.5+. Available example applications, support, and contributions.
In the beginning, there was the Google (SOAP) Search API. In December 2006, Google no longer issued any new keys for this API. Those with keys already could still use the API, but it was effectively deprecated.