I was not able to find a working example on how to query Elasticsearch using the completion suggester in PHP (elasticsearch-php).
Querying via CURL, e.g.
The PHP ES client has a method called suggest that you can use for that purpose:
$params = [ 'index' => 'tstidx', 'body' => [ 'try' => [ 'text' => 'a', 'completion' => [ 'field' => 'suggest' ] ] ] ]; $client = ClientBuilder::create()->build(); $response = $client->suggest($params);