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API endpoints

There are a huge number of API endpoints Elasticsearch provides (see list of REST APIs) to search documents, set up index mappings, test analyzers or explain queries. Here is a list of useful API endpoints that are helpful when creating your own index mappings with analyzers.

These APIs assume there is an Elasticsearch instance running at localhost:9200.

Search API

The Search API endpoint is available for every index, it's the main endpoint of all search related APIs (see overview of Search APIs). This endpoint is used whenever a search request is sent to an Elasticsearch Index.

For example assuming there is an index named test, a basic search request using the /test/_search endpoint looks as follows:

curl -X GET "localhost:9200/test/_search" -H 'Content-Type: application/json' -d '{}'

When successful the response contains the search results and meta data. Examples in the Query chapter use the Search API endpoint.

Analyze API

The Analyze API can be used to test how Elasticsearch (or Lucene) analyzes text strings to return a list of tokens.

For example to test the output of the standard analyzer via curl the general /_analyze endpoint can be used.

✅ Run the following query against the Analyze API.

curl -X GET "localhost:9200/_analyze?pretty" -H 'Content-Type: application/json' -d '{
  "analyzer" : "standard",
  "text" : ["Bart Simpsons is a comic character"]
}'

The /_analyze API endpoint returns the following list of tokens:

["bart", "simpsons", "is", "a", "comic", "character"]

All tokens are lower cased.

💡 Tip: the ?pretty query argument in the URL above returns more human friendly formatted output.

There is more information returned, e.g. offsets, position, the complete output looks like:

{
  "tokens" : [
    {
      "token" : "bart",
      "start_offset" : 0,
      "end_offset" : 4,
      "type" : "<ALPHANUM>",
      "position" : 0
    },
    {
      "token" : "simpsons",
      "start_offset" : 5,
      "end_offset" : 13,
      "type" : "<ALPHANUM>",
      "position" : 1
    },
    {
      "token" : "is",
      "start_offset" : 14,
      "end_offset" : 16,
      "type" : "<ALPHANUM>",
      "position" : 2
    },
    {
      "token" : "a",
      "start_offset" : 17,
      "end_offset" : 18,
      "type" : "<ALPHANUM>",
      "position" : 3
    },
    {
      "token" : "comic",
      "start_offset" : 19,
      "end_offset" : 24,
      "type" : "<ALPHANUM>",
      "position" : 4
    },
    {
      "token" : "character",
      "start_offset" : 25,
      "end_offset" : 34,
      "type" : "<ALPHANUM>",
      "position" : 5
    }
  ]
}

Cat APIs

Elasticsearch offers a list of API endpoints to return compact and aligned text (CAT) formatted output. Here is a list of a few endpoints that help to get information on cluster, nodes, indices, aliases etc.

See cat health API documentation.

✅ Display the health of the Elasticsearch cluster

curl -X GET 'http://localhost:9200/_cat/health?v'

See cat nodes API documentation.

✅ List all nodes in the Elasticsearch cluster

curl -X GET 'http://localhost:9200/_cat/nodes?v'

This command outputs the list of all available nodes with some basic metrics on heap, memory, cpu, load.

See cat indices API documentation.

✅ List all indices from all nodes

curl -X GET 'http://localhost:9200/_cat/indices?v'

or to output information for a specific inddex

curl -X GET 'http://localhost:9200/_cat/indices/<index>?v'

See cat shards API

✅ List all shards of all indices

curl -X GET 'http://localhost:9200/_cat/shards?v'