Dowser.Opensearch.Codec.Date (Dowser.Opensearch v0.1.0)

date — ISO-8601 strings or epoch millis <-> DateTime.

A mapping entry with no "format" is treated as OpenSearch's own default, strict_date_optional_time||epoch_millis. Custom Java date formats aren't parsed; unrecognized strings pass through untouched (write your own codec over these types to handle them).