yes, you can enable the elasticsearch API ("es.api.enabled: true" in the crate.yml config file). however, it's not officially supported and we recommend to use it read-only as we store additional information about tables,...
Crate-only queries - like exact counts, distinct counts, (soon JOINs) - are not exposed via this API. The Crate query engine is accessing Lucene directly and not running on top of the ES query engine.
Is there specific "Crate" query syntax for selects that is not supported by the Elasticsearch DSL?