Google Search has had autocomplete functionality for a while now; and as with most things someone has reverse-engineered it and an unpublished API has been in use for quiet a while now – allowing webmasters to incorporate Google’s autocomplete functionality into their own websites. However Google never intended for this to happen – so as of August 10th, 2015 Google will restrict unauthorized access to the Autocomplete API.
We want to ensure that users experience autocomplete as it was designed to be used — as a service closely tied to Search. We believe this provides the best user experience for both services.
For any webmasters who still wish to use the autocomplete service on their website Google recommends the Google Custom Search Engine which will continue to maintain autocomplete functionality.