All Elasticsearch REST APIs support the following options.

Pretty Resultsedit

When appending ?pretty=true to any request made, the JSON returned will be pretty formatted (use it for debugging only!). Another option is to set ?format=yaml which will cause the result to be returned in the (sometimes) more readable yaml format.

Human readable outputedit

Statistics are returned in a format suitable for humans (e.g. "exists_time": "1h" or "size": "1kb") and for computers (e.g. "exists_time_in_millis": 3600000 or "size_in_bytes": 1024). The human readable values can be turned off by adding ?human=false to the query string. This makes sense when the stats results are being consumed by a monitoring tool, rather than intended for human consumption. The default for the human flag is false.

Date Mathedit

Most parameters which accept a formatted date value — such as gt and lt in range queries, or from and to in daterange aggregations — understand date maths.

The expression starts with an anchor date, which can either be now, or a date string ending with ||. This anchor date can optionally be followed by one or more maths expressions:

The supported time units differ from those supported by time units for durations. The supported units are:

Assuming now is 2001-01-01 12:00:00, some examples are:

Response Filteringedit

All REST APIs accept a filter_path parameter that can be used to reduce the response returned by Elasticsearch. This parameter takes a comma separated list of filters expressed with the dot notation:

GET /_search?q=kimchy&filter_path=took,hits.hits._id,hits.hits._score

Responds:

{
  "took" : 3,
  "hits" : {
    "hits" : [
      {
        "_id" : "0",
        "_score" : 1.6375021
      }
    ]
  }
}

It also supports the * wildcard character to match any field or part of a field’s name:

GET /_cluster/state?filter_path=metadata.indices.*.stat*

Responds:

{
  "metadata" : {
    "indices" : {
      "my-index-000001": {"state": "open"}
    }
  }
}

And the ** wildcard can be used to include fields without knowing the exact path of the field. For example, we can return the state of every shard with this request:

GET /_cluster/state?filter_path=routing_table.indices.**.state

Responds:

{
  "routing_table": {
    "indices": {
      "my-index-000001": {
        "shards": {
          "0": [{"state": "STARTED"}, {"state": "UNASSIGNED"}]
        }
      }
    }
  }
}

It is also possible to exclude one or more fields by prefixing the filter with the char -:

GET /_count?filter_path=-_shards

Responds:

{
  "count" : 5
}

And for more control, both inclusive and exclusive filters can be combined in the same expression. In this case, the exclusive filters will be applied first and the result will be filtered again using the inclusive filters:

GET /_cluster/state?filter_path=metadata.indices.*.state,-metadata.indices.logstash-*

Responds:

{
  "metadata" : {
    "indices" : {
      "my-index-000001" : {"state" : "open"},
      "my-index-000002" : {"state" : "open"},
      "my-index-000003" : {"state" : "open"}
    }
  }
}

Note that Elasticsearch sometimes returns directly the raw value of a field, like the _source field. If you want to filter _source fields, you should consider combining the already existing _source parameter (see Get API for more details) with the filter_path parameter like this:

POST /library/_doc?refresh
{"title": "Book #1", "rating": 200.1}
POST /library/_doc?refresh
{"title": "Book #2", "rating": 1.7}
POST /library/_doc?refresh
{"title": "Book #3", "rating": 0.1}
GET /_search?filter_path=hits.hits._source&_source=title&sort=rating:desc

{
  "hits" : {
    "hits" : [ {
      "_source":{"title":"Book #1"}
    }, {
      "_source":{"title":"Book #2"}
    }, {
      "_source":{"title":"Book #3"}
    } ]
  }
}

Flat Settingsedit

The flat_settings flag affects rendering of the lists of settings. When the flat_settings flag is true, settings are returned in a flat format:

GET my-index-000001/_settings?flat_settings=true

Returns:

{
  "my-index-000001" : {
    "settings": {
      "index.number_of_replicas": "1",
      "index.number_of_shards": "1",
      "index.creation_date": "1474389951325",
      "index.uuid": "n6gzFZTgS664GUfx0Xrpjw",
      "index.version.created": ...,
      "index.routing.allocation.include._tier_preference" : "data_content",
      "index.provided_name" : "my-index-000001"
    }
  }
}

When the flat_settings flag is false, settings are returned in a more human readable structured format:

GET my-index-000001/_settings?flat_settings=false

Returns:

{
  "my-index-000001" : {
    "settings" : {
      "index" : {
        "number_of_replicas": "1",
        "number_of_shards": "1",
        "creation_date": "1474389951325",
        "uuid": "n6gzFZTgS664GUfx0Xrpjw",
        "version": {
          "created": ...
        },
        "routing": {
          "allocation": {
            "include": {
              "_tier_preference": "data_content"
            }
          }
        },
        "provided_name" : "my-index-000001"
      }
    }
  }
}

By default flat_settings is set to false.

Fuzzinessedit

Some queries and APIs support parameters to allow inexact fuzzy matching, using the fuzziness parameter.

When querying text or keyword fields, fuzziness is interpreted as a Levenshtein Edit Distance — the number of one character changes that need to be made to one string to make it the same as another string.

The fuzziness parameter can be specified as:

Enabling stack tracesedit

By default when a request returns an error Elasticsearch doesn’t include the stack trace of the error. You can enable that behavior by setting the error_trace url parameter to true. For example, by default when you send an invalid size parameter to the _search API:

POST /my-index-000001/_search?size=surprise_me

The response looks like:

{
  "error" : {
    "root_cause" : [
      {
        "type" : "illegal_argument_exception",
        "reason" : "Failed to parse int parameter [size] with value [surprise_me]"
      }
    ],
    "type" : "illegal_argument_exception",
    "reason" : "Failed to parse int parameter [size] with value [surprise_me]",
    "caused_by" : {
      "type" : "number_format_exception",
      "reason" : "For input string: \"surprise_me\""
    }
  },
  "status" : 400
}

But if you set error_trace=true:

POST /my-index-000001/_search?size=surprise_me&error_trace=true

The response looks like:

{
  "error": {
    "root_cause": [
      {
        "type": "illegal_argument_exception",
        "reason": "Failed to parse int parameter [size] with value [surprise_me]",
        "stack_trace": "Failed to parse int parameter [size] with value [surprise_me]]; nested: IllegalArgumentException..."
      }
    ],
    "type": "illegal_argument_exception",
    "reason": "Failed to parse int parameter [size] with value [surprise_me]",
    "stack_trace": "java.lang.IllegalArgumentException: Failed to parse int parameter [size] with value [surprise_me]\n    at org.elasticsearch.rest.RestRequest.paramAsInt(RestRequest.java:175)...",
    "caused_by": {
      "type": "number_format_exception",
      "reason": "For input string: \"surprise_me\"",
      "stack_trace": "java.lang.NumberFormatException: For input string: \"surprise_me\"\n    at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)..."
    }
  },
  "status": 400
}