[[mapping-meta-field]]
=== `_meta` field

Each mapping type can have custom meta data associated with it. These are not
used at all by Elasticsearch, but can be used to store application-specific
metadata, such as the class that a document belongs to:

[source,js]
--------------------------------------------------
PUT my_index
{
  "mappings": {
    "user": {
      "_meta": { <1>
        "class": "MyApp::User",
        "version": {
          "min": "1.0",
          "max": "1.3"
        }
      }
    }
  }
}
--------------------------------------------------
// AUTOSENSE
<1> This `_meta` info can be retrieved with the
    <<indices-get-mapping,GET mapping>> API.

The `_meta` field can be updated on an existing type using the
<<indices-put-mapping,PUT mapping>> API.