[role="xpack"]
[[post-inference-api]]
=== Perform inference API

experimental[]

Performs an inference task on an input text by using an {infer} endpoint.

IMPORTANT: The {infer} APIs enable you to use certain services, such as built-in {ml} models (ELSER, E5), models uploaded through Eland, Cohere, OpenAI, Azure, Google AI Studio, Google Vertex AI, Anthropic, Watsonx.ai, or Hugging Face.
For built-in models and models uploaded through Eland, the {infer} APIs offer an alternative way to use and manage trained models.
However, if you do not plan to use the {infer} APIs to use these models or if you want to use non-NLP models, use the <<ml-df-trained-models-apis>>.


[discrete]
[[post-inference-api-request]]
==== {api-request-title}

`POST /_inference/<inference_id>`

`POST /_inference/<task_type>/<inference_id>`


[discrete]
[[post-inference-api-prereqs]]
==== {api-prereq-title}

* Requires the `monitor_inference` <<privileges-list-cluster,cluster privilege>>
(the built-in `inference_admin` and `inference_user` roles grant this privilege)

[discrete]
[[post-inference-api-desc]]
==== {api-description-title}

The perform {infer} API enables you to use {ml} models to perform specific tasks
on data that you provide as an input. The API returns a response with the
results of the tasks. The {infer} endpoint you use can perform one specific task
that has been defined when the endpoint was created with the
<<put-inference-api>>.


[discrete]
[[post-inference-api-path-params]]
==== {api-path-parms-title}

`<inference_id>`::
(Required, string)
The unique identifier of the {infer} endpoint.


`<task_type>`::
(Optional, string)
The type of {infer} task that the model performs.


[discrete]
[[post-inference-api-query-params]]
==== {api-query-parms-title}

`timeout`::
(Optional, timeout)
Controls the amount of time to wait for the inference to complete. Defaults to 30
seconds.

[discrete]
[[post-inference-api-request-body]]
==== {api-request-body-title}

`input`::
(Required, string or array of strings)
The text on which you want to perform the {infer} task.
`input` can be a single string or an array.
+
--
[NOTE]
====
Inference endpoints for the `completion` task type currently only support a
single string as input.
====
--

`query`::
(Required, string)
Only for `rerank` {infer} endpoints. The search query text.

`task_settings`::
(Optional, object)
Task settings for the individual {infer} request.
These settings are specific to the `<task_type>` you specified and override the task settings specified when initializing the service.

[discrete]
[[post-inference-api-example]]
==== {api-examples-title}


[discrete]
[[inference-example-completion]]
===== Completion example

The following example performs a completion on the example question.


[source,console]
------------------------------------------------------------
POST _inference/completion/openai_chat_completions
{
  "input": "What is Elastic?"
}
------------------------------------------------------------
// TEST[skip:TBD]


The API returns the following response:


[source,console-result]
------------------------------------------------------------
{
  "completion": [
    {
      "result": "Elastic is a company that provides a range of software solutions for search, logging, security, and analytics. Their flagship product is Elasticsearch, an open-source, distributed search engine that allows users to search, analyze, and visualize large volumes of data in real-time. Elastic also offers products such as Kibana, a data visualization tool, and Logstash, a log management and pipeline tool, as well as various other tools and solutions for data analysis and management."
    }
  ]
}
------------------------------------------------------------
// NOTCONSOLE

[discrete]
[[inference-example-rerank]]
===== Rerank example

The following example performs reranking on the example input.

[source,console]
------------------------------------------------------------
POST _inference/rerank/cohere_rerank
{
  "input": ["luke", "like", "leia", "chewy","r2d2", "star", "wars"],
  "query": "star wars main character"
}
------------------------------------------------------------
// TEST[skip:TBD]

The API returns the following response:


[source,console-result]
------------------------------------------------------------
{
  "rerank": [
    {
      "index": "2",
      "relevance_score": "0.011597361",
      "text": "leia"
    },
    {
      "index": "0",
      "relevance_score": "0.006338922",
      "text": "luke"
    },
    {
      "index": "5",
      "relevance_score": "0.0016166499",
      "text": "star"
    },
    {
      "index": "4",
      "relevance_score": "0.0011695103",
      "text": "r2d2"
    },
    {
      "index": "1",
      "relevance_score": "5.614787E-4",
      "text": "like"
    },
    {
      "index": "6",
      "relevance_score": "3.7850367E-4",
      "text": "wars"
    },
    {
      "index": "3",
      "relevance_score": "1.2508839E-5",
      "text": "chewy"
    }
  ]
}
------------------------------------------------------------


[discrete]
[[inference-example-sparse]]
===== Sparse embedding example

The following example performs sparse embedding on the example sentence.


[source,console]
------------------------------------------------------------
POST _inference/sparse_embedding/my-elser-model
{
  "input": "The sky above the port was the color of television tuned to a dead channel."
}
------------------------------------------------------------
// TEST[skip:TBD]


The API returns the following response:


[source,console-result]
------------------------------------------------------------
{
  "sparse_embedding": [
    {
      "port": 2.1259406,
      "sky": 1.7073475,
      "color": 1.6922266,
      "dead": 1.6247464,
      "television": 1.3525393,
      "above": 1.2425821,
      "tuned": 1.1440028,
      "colors": 1.1218185,
      "tv": 1.0111054,
      "ports": 1.0067928,
      "poem": 1.0042328,
      "channel": 0.99471164,
      "tune": 0.96235967,
      "scene": 0.9020516,
      (...)
    },
    (...)
  ]
}
------------------------------------------------------------
// NOTCONSOLE

[discrete]
[[inference-example-text-embedding]]
===== Text embedding example

The following example performs text embedding on the example sentence using the Cohere integration.


[source,console]
------------------------------------------------------------
POST _inference/text_embedding/my-cohere-endpoint
{
  "input": "The sky above the port was the color of television tuned to a dead channel.",
  "task_settings": {
    "input_type": "ingest"
  }
}
------------------------------------------------------------
// TEST[skip:TBD]


The API returns the following response:


[source,console-result]
------------------------------------------------------------
{
  "text_embedding": [
    {
      "embedding": [
        {
          0.018569946,
          -0.036895752,
          0.01486969,
          -0.0045204163,
          -0.04385376,
          0.0075950623,
          0.04260254,
          -0.004005432,
          0.007865906,
          0.030792236,
          -0.050476074,
          0.011795044,
          -0.011642456,
          -0.010070801,
          (...)
        },
        (...)
      ]
    }
  ]
}
------------------------------------------------------------
// NOTCONSOLE
