acp is the AFS v7 web service in charge of providing completions, or search suggestions, to users. It predicts the queries that users want to type in before they type them in completely.
acp provides fast and accurate results. Its output formats are specially designed for easy integration in AJAX pages (JSON, JSONP, OpenSearch).
For example, the following URL shows a call to the "1" acp service on the "server" host with the "qu" query: