Access to autocomplete API to unauthorized users has been blocked by Google starting from August 10, 2015. Announcing this, Google stated that they want the users’ experience of autocomplete API exactly as it was meant to be used – a service closely tied to Search.
Autocomplete service would predict a query before a user finishes typing. Many developers used a non-official, non-published API to integrate the results of autocomplete within their own services. Developers who were able to dig into the autocomplete API gained the ability to incorporate autocomplete services, independent of Google Search. This was reverse engineering using an unpublished API.
Google holds that the API is being used in useful as well as not-so-useful ways. When used out-of-context, autocomplete API doesn’t provide a meaningful service.
To quote Peter Chiu from Google
“For publishers and developers who still want to use the autocomplete service for their site, we have an alternative. Google Custom Search Engine [CSE] allows sites to maintain autocomplete functionality in connection with Search functionality. Any partner already using Google CSE will be unaffected by this change. For others, if you want autocomplete functionality after August 10th, 2015, please see our CSE sign-up page.”
This step of Google is likely to affect those SEM and keyword tools as well that use autocomplete API to generate new keyword ideas, so search marketing industry may not exactly appreciate this.Google to Bid Goodbye to Autocomplete API On August 10!,