> ## Documentation Index
> Fetch the complete documentation index at: https://algolia.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Create a replica index

> Replica indices let you use different ranking strategies, such as sorting.

export const Application = () => <Tooltip tip="An Algolia application is a self-contained environment with its own indices, configuration, and API keys. Applications don't share data or settings with each other.">
    application
  </Tooltip>;

export const AlgoliaSearch = () => <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 80 80" width="20" height="20" className="inline" fill="none" role="presentation" ariaLabel="Algolia Search">
    <circle cx="40" cy="32" r="28" fill="#5468FF"></circle>
    <rect x="30" y="22" width="20" height="20" rx="10" fill="#fff"></rect>
    <path d="M43 63.5 54.5 60l6 17h-12L43 63.5Z" fill="#36395A"></path>
  </svg>;

Algolia uses one ranking strategy per index.
If you want to use different rankings for the same data,
you can use [replica indices](/doc/guides/managing-results/refine-results/sorting/in-depth/replicas).

## Standard and virtual replicas

Standard replicas are exact copies of your index.
They let you to have a completely different configuration of your index,
while keeping the data in sync with your primary index.

[Virtual replicas](/doc/guides/managing-results/refine-results/sorting/in-depth/replicas) are an optional feature that references a primary index instead of duplicating it.
They're more efficient than standard replicas but you can only change a subset of the index settings.
Virtual replicas are optimized for [relevant sorting](/doc/guides/managing-results/refine-results/sorting/in-depth/relevant-sort).

<Callout icon="credit-card" color="#c084fc">
  This feature isn't available on every plan.
  Refer to your [pricing plan](https://www.algolia.com/pricing) to see if it's included.
</Callout>

## Naming replica indices

To help you identify your replica indices,
you should adopt a naming pattern,
such as `{primaryIndex}_{sortingAttribute}_{asc_or_desc}`.
For example, `products_price_desc` is a replica index of your `products` index,
where the results are sorted by the `price` attribute in descending order.

## Create replica indices in the dashboard

1. Go to the [Algolia dashboard](https://dashboard.algolia.com/explorer/browse) and select your Algolia <Application />.
2. On the left sidebar, select <AlgoliaSearch /> **Search**.
3. Select your Algolia index.
4. On the **Replicas** tab, click **Create Replica Index**.
5. In the **Create a new replica** dialog,
   select **Standard Replica (default)** or **Virtual Replica for Relevant Sort**,
   enter a name for your replica, and click **Create replica**.
6. You can add multiple replicas at once.
7. Click **Review and Save Settings**.

## Create replica indices with the API

To create replica indices,
use the [`replicas`](/doc/api-reference/api-parameters/replicas) setting in your primary index.

To run the code examples on this page, [install the latest API client](/doc/libraries/sdk/install).

<CodeGroup>
  ```cs C# theme={"system"}
  var response = await client.SetSettingsAsync(
    "INDEX_NAME",
    new IndexSettings { Replicas = new List<string> { "products_price_desc" } }
  );
  ```

  ```dart Dart theme={"system"}
  final response = await client.setSettings(
    indexName: "INDEX_NAME",
    indexSettings: IndexSettings(
      replicas: [
        "products_price_desc",
      ],
    ),
  );
  ```

  ```go Go theme={"system"}
  response, err := client.SetSettings(client.NewApiSetSettingsRequest(
    "INDEX_NAME",
    search.NewEmptyIndexSettings().SetReplicas(
      []string{"products_price_desc"})))
  if err != nil {
    // handle the eventual error
    panic(err)
  }
  ```

  ```java Java theme={"system"}
  UpdatedAtResponse response = client.setSettings(
    "INDEX_NAME",
    new IndexSettings().setReplicas(Arrays.asList("products_price_desc"))
  );
  ```

  ```js JavaScript theme={"system"}
  const response = await client.setSettings({
    indexName: 'theIndexName',
    indexSettings: { replicas: ['products_price_desc'] },
  });
  ```

  ```kotlin Kotlin theme={"system"}
  var response =
    client.setSettings(
      indexName = "INDEX_NAME",
      indexSettings = IndexSettings(replicas = listOf("products_price_desc")),
    )
  ```

  ```php PHP theme={"system"}
  $response = $client->setSettings(
      'INDEX_NAME',
      ['replicas' => [
          'products_price_desc',
      ],
      ],
  );
  ```

  ```python Python theme={"system"}
  response = client.set_settings(
      index_name="INDEX_NAME",
      index_settings={
          "replicas": [
              "products_price_desc",
          ],
      },
  )
  ```

  ```ruby Ruby theme={"system"}
  response = client.set_settings(
    "INDEX_NAME",
    Algolia::Search::IndexSettings.new(replicas: ["products_price_desc"])
  )
  ```

  ```scala Scala theme={"system"}
  val response = Await.result(
    client.setSettings(
      indexName = "INDEX_NAME",
      indexSettings = IndexSettings(
        replicas = Some(Seq("products_price_desc"))
      )
    ),
    Duration(100, "sec")
  )
  ```

  ```swift Swift theme={"system"}
  let response = try await client.setSettings(
      indexName: "INDEX_NAME",
      indexSettings: IndexSettings(replicas: ["products_price_desc"])
  )
  ```
</CodeGroup>

To create virtual indices, use the `virtual` modifier for the replica index name:

<CodeGroup>
  ```cs C# theme={"system"}
  var response = await client.SetSettingsAsync(
    "INDEX_NAME",
    new IndexSettings { Replicas = new List<string> { "virtual(products_price_desc)" } }
  );
  ```

  ```dart Dart theme={"system"}
  final response = await client.setSettings(
    indexName: "INDEX_NAME",
    indexSettings: IndexSettings(
      replicas: [
        "virtual(products_price_desc)",
      ],
    ),
  );
  ```

  ```go Go theme={"system"}
  response, err := client.SetSettings(client.NewApiSetSettingsRequest(
    "INDEX_NAME",
    search.NewEmptyIndexSettings().SetReplicas(
      []string{"virtual(products_price_desc)"})))
  if err != nil {
    // handle the eventual error
    panic(err)
  }
  ```

  ```java Java theme={"system"}
  UpdatedAtResponse response = client.setSettings(
    "INDEX_NAME",
    new IndexSettings().setReplicas(Arrays.asList("virtual(products_price_desc)"))
  );
  ```

  ```js JavaScript theme={"system"}
  const response = await client.setSettings({
    indexName: 'theIndexName',
    indexSettings: { replicas: ['virtual(products_price_desc)'] },
  });
  ```

  ```kotlin Kotlin theme={"system"}
  var response =
    client.setSettings(
      indexName = "INDEX_NAME",
      indexSettings = IndexSettings(replicas = listOf("virtual(products_price_desc)")),
    )
  ```

  ```php PHP theme={"system"}
  $response = $client->setSettings(
      'INDEX_NAME',
      ['replicas' => [
          'virtual(products_price_desc)',
      ],
      ],
  );
  ```

  ```python Python theme={"system"}
  response = client.set_settings(
      index_name="INDEX_NAME",
      index_settings={
          "replicas": [
              "virtual(products_price_desc)",
          ],
      },
  )
  ```

  ```ruby Ruby theme={"system"}
  response = client.set_settings(
    "INDEX_NAME",
    Algolia::Search::IndexSettings.new(replicas: ["virtual(products_price_desc)"])
  )
  ```

  ```scala Scala theme={"system"}
  val response = Await.result(
    client.setSettings(
      indexName = "INDEX_NAME",
      indexSettings = IndexSettings(
        replicas = Some(Seq("virtual(products_price_desc)"))
      )
    ),
    Duration(100, "sec")
  )
  ```

  ```swift Swift theme={"system"}
  let response = try await client.setSettings(
      indexName: "INDEX_NAME",
      indexSettings: IndexSettings(replicas: ["virtual(products_price_desc)"])
  )
  ```
</CodeGroup>

## Next steps

After creating your replica indices,
you can change their settings—for example,
by adding a [attribute for sorting](/doc/guides/managing-results/refine-results/sorting/how-to/sort-by-attribute).