Query autocompletions

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for obtaining query completions. In one aspect, a method includes receiving a query input in a search engine query input field in a user interface. The method also includes submitting the query input as a first query stem to an autocompletion module. The method also includes receiving a first response from the autocompletion module, the first response providing no first query autocompletions. The method also includes submitting a second query stem to the autocompletion module, the second query stem being the first query stem with a first prefix removed. The method also includes receiving a second response from the autocompletion module including one or more second autocompletions satisfying a second quality test. The method also includes providing second autocompletions for presentation on the user interface.