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data-explorer/kusto/query/dax-request-plugin.md

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+---
+title:  dax_request plugin
+description: Learn how to use the dax_request plugin to send a DAX query to a DAX server network endpoint. 
+ms.reviewer: gabil
+ms.topic: reference
+ms.date: 10/11/2026
+monikerRange: "microsoft-fabric || azure-data-explorer"
+---
+
+# dax_request plugin
+
+The `dax_request` plugin runs a Data Analysis Expressions (DAX) query against a Power BI semantic model and returns the results as a table. Process the returned table with standard Kusto Query Language (KQL) operators. Invoke the plugin with the [evaluate operator](evaluate-operator.md).
+
+The plugin uses the Power BI [Execute DAX Queries API](/power-bi/developer/execute-dax-queries-arrow/overview), which returns results in Apache Arrow format. The plugin preserves supported column types when it converts the response to a KQL table.
+
+## Prerequisites
+
+* The semantic model must be in a workspace assigned to a Fabric or Power BI Premium capacity.
+* The **Dataset Execute Queries REST API**, **Allow XMLA endpoints and Analyze in Excel with on-premises semantic models** tenant settings must be enabled.
+* You must have [Build permission](/power-bi/connect-data/service-datasets-permissions) on the semantic model.
+* The cluster callout policy must allow `dax` callouts to `api.powerbi.com`. To change this policy, you need `AllDatabasesAdmin` or `Ops` permissions.
+
+## Syntax
+
+`evaluate` ``dax_request`` `(`*ConnectionString*`,`*DaxQuery*`)` [`:` *OutputSchema*]
+
+Learn more about syntax conventions in the [Syntax conventions for reference documentation](syntax-conventions.md).
+
+## Parameters
+
+| Name | Type | Required| Description |
+|---|---|---|---|
+| ConnectionString | `string` | Yes | The semantic model URL followed by `;Impersonate`. For the supported URL formats, see [Connection string](#connection-string). |
+| DaxQuery | `string` | Yes | The DAX query to execute against the semantic model. |
+| OutputSchema | `string` | - | The names and types of the expected output columns. Use the syntax `(`*ColumnName*`:`*ColumnType* [`,` ...]`)`. |
+
+> ![NOTE]
+> Specifying *OutputSchema* is recommended because it enables scenarios such as distributed queries and allows query optimizations. The plugin returns an error if the runtime schema doesn't match *OutputSchema*.
+
+## Connection string
+
+The connection string consists of the semantic model URL and the `;Impersonate` authentication directive. Use one of the following formats:
+
+* Semantic model in a workspace:
+    `https://api.powerbi.com/v1.0/myorg/groups/`*WorkspaceId*`/datasets/`*SemanticModelId*`;Impersonate`
+
+* Semantic model in My workspace:
+    `https://api.powerbi.com/v1.0/myorg/datasets/`*SemanticModelId*`;Impersonate`
+
+The `myorg` path segment is literal. `*WorkspaceId*` and `*SemanticModelId*` must be globally unique identifiers (GUIDs). Don't include a query string, fragment, or trailing path after *SemanticModelId*.
+
+## Authentication and authorization
+
+The plugin uses Microsoft Entra on-behalf-of authentication. The engine obtains a token for the requesting user and sends the DAX query in that user's security context. The user must have Build permission on the semantic model. Any row-level security or object-level security configured for the user applies to the query.
+
+Use `;Impersonate` as the authentication directive. Managed identity, service principal, and application key authentication aren't supported.
+
+> [!IMPORTANT]
+> Use an [obfuscated string literal](scalar-data-types/string.md) for any string that contains confidential information. Obfuscated values don't appear in Kusto tracing.
+
+## Configure and callout policy
+
+The plugin makes an external call to Power BI. Because the default callout policy blocks `dax` callouts, a cluster administrator must explicitly allow the Power BI endpoint.
+
+The following command merges a restrictive `dax` rule into the existing [cluster callout policy](../management/callout-policy.md):
+
+```kusto
+.alter-merge cluster policy callout @'[{
+  "CalloutType": "dax",
+  "CalloutUriRegex": "api\\.powerbi\\.com.*",
+  "CanCall": true
+}]'
+```
+
+Verify the policy:
+
+```kusto
+.show cluster policy callout
+```
+
+## Returns
+
+The plugin returns the DAX query result as a KQL table. It preserves supported Arrow data types. For example, Arrow `int64`, `double`, `utf8`, and `date-time` values map to Kusto `long`, `real`, `string`, and `datetime`, respectively.
+
+Power BI returns bracketed column names, such as `[Category]`. In KQL, reference these names with the `['...']` syntax, such as `['[Category]']`.
+
+## Examples
+
+### Return all rows from a table
+
+The following example returns all rows from the `Sales` table:
+
+```kusto
+evaluate dax_request(
+  'https://api.powerbi.com/v1.0/myorg/groups/<workspace-id>/datasets/<semantic-model-id>;Impersonate',
+  'EVALUATE Sales')
+```
+
+### Process DAX results with Kusto
+
+The following example selects two columns in DAX, summarizes the result in KQL, and filters by category:
+
+```kusto
+evaluate dax_request(
+  'https://api.powerbi.com/v1.0/myorg/groups/<workspace-id>/datasets/<semantic-model-id>;Impersonate',
+  'EVALUATE SELECTCOLUMNS(Sales, "Category", Sales[Category], "Amount", Sales[Amount])')
+| summarize TotalAmount = sum(['[Amount]']) by ['[Category]']
+| where ['[Category]'] == 'Electronics'
+```
+
+> [!TIP]
+> Filter and aggregate data in DAX when possible to reduce the amount of data returned to Kusto.
+
+### Specify an output schema
+
+The following example declares an output schema to use the distributed execution path. The declared schema must match the live result schema.
+
+```kusto
+evaluate dax_request(
+  'https://api.powerbi.com/v1.0/myorg/groups/<workspace-id>/datasets/<semantic-model-id>;Impersonate',
+  'EVALUATE ROW("cnt", COUNTROWS(Sales), "sumAmt", SUM(Sales[Amount]))')
+  : (['[cnt]']:long, ['[sumAmt]']:real)
+```
+
+## Troubleshooting
+
+| Error | Cause and resolution |
+|---|---|
+| Invalid connection string | Confirm that the URL uses a supported format, the workspace and semantic model IDs are valid GUIDs, and the string ends with `;Impersonate`. |
+| Callout isn't permitted | Configure the cluster callout policy to allow `dax` calls to `api.powerbi.com`. |
+| Authentication or authorization error | Confirm that the required tenant settings are enabled and that the requesting user has Build permission on the semantic model. |
+| HTTP request error | Ensure Power BI service availability, endpoint accessibility, and the semantic model URL. |

data-explorer/kusto/query/toc.yml

@@ -1703,6 +1703,8 @@ items:
             href: azure-digital-twins-query-request-plugin.md
           - name: cosmosdb_sql_request plugin
             href: cosmosdb-plugin.md
+          - name: dax_request plugin
+            href: dax-request-plugin.md
           - name: http_request plugin
             href: http-request-plugin.md
           - name: http_request_post plugin