Query/management HTTP request

Applies to: ✅ Microsoft Fabric ✅ Azure Data Explorer

Request verb and resource

Action	HTTP verb	HTTP resource
Query	GET	/v1/rest/query
Query	POST	/v1/rest/query
Query v2	GET	/v2/rest/query
Query v2	POST	/v2/rest/query
Management	POST	/v1/rest/mgmt

For example, to send a management command ("management") to a service endpoint, use the following request line:

POST https://help.kusto.windows.net/v1/rest/mgmt HTTP/1.1

See Request headers and Body to learn what to include.

Request headers

The following table contains the common headers used for query and management operations.

Standard header	Description	Required/Optional
Accept	The media types the client receives. Set to application/json.	Required
Accept-Encoding	The supported content encodings. Supported encodings are gzip and deflate.	Optional
Authorization	The authentication credentials. For more information, see authentication.	Required
Connection	Whether the connection stays open after the operation. The recommendation is to set Connection to Keep-Alive.	Optional
Content-Length	The size of the request body. Specify the request body length when known.	Optional
Content-Type	The media type of the request body. Set to application/json with charset=utf-8.	Required
Expect	The expected response from the server. It can be set to 100-Continue.	Optional
Host	The qualified domain name that the request was sent to. For example, help.kusto.windows.net.	Required

The following table contains the common custom headers used for query and management operations. Unless noted, these headers are used only for telemetry purposes and don’t affect functionality.

All headers are optional. However, We recommend specifying the x-ms-client-request-id custom header. In some scenarios, such as canceling a running query, x-ms-client-request-id is required since it's used to identify the request.

Custom header	Description
x-ms-app	The friendly name of the application making the request.
x-ms-user	The friendly name of the user making the request.
x-ms-user-id	The same friendly name as x-ms-user.
x-ms-client-request-id	A unique identifier for the request.
x-ms-client-version	The friendly version identifier for the client making the request.
x-ms-readonly	If specified, it forces the request to run in read-only mode which prevents the request from changing data.

Request parameters

The following parameters can be passed in the request. They're encoded in the request as query parameters or as part of the body, depending on whether GET or POST is used.

Parameter	Description	Required/Optional
csl	The text of the query or management command to execute.	Required
db	The name of the database that is the target of the query or management command.	Optional for some management commands. Required for all queries and all other commands.
properties	Request properties that modify how the request is processed and its results. For more information, see Request properties.	Optional

GET query parameters

When a GET request is used, the query parameters specify the request parameters.

Body

When a POST request is used, the body of the request contains a single UTF-8 encoded JSON document, which includes the values of the request parameters.

Examples

The following example shows the HTTP POST request for a query.

POST https://help.kusto.windows.net/v2/rest/query HTTP/1.1

Request headers

Accept: application/json
Authorization: Bearer ...AzureActiveDirectoryAccessToken...
Accept-Encoding: deflate
Content-Type: application/json; charset=utf-8
Host: help.kusto.windows.net
x-ms-client-request-id: MyApp.Query;e9f884e4-90f0-404a-8e8b-01d883023bf1
x-ms-user-id: EARTH\davidbg
x-ms-app: MyApp

Request body

{
  "db":"Samples",
  "csl":"print Test=\"Hello, World!\"",
  "properties":"{\"Options\":{\"queryconsistency\":\"strongconsistency\"},\"Parameters\":{},\"ClientRequestId\":\"MyApp.Query;e9f884e4-90f0-404a-8e8b-01d883023bf1\"}"
}

The following example shows how to create a request that sends the previous query, using curl.

1. Obtain a token for authentication.

   Replace AAD_TENANT_NAME_OR_ID, AAD_APPLICATION_ID, and AAD_APPLICATION_KEY with the relevant values, after setting up Microsoft Entra application authentication.

   curl "https://login.microsoftonline.com/AAD_TENANT_NAME_OR_ID/oauth2/token" \
     -F "grant_type=client_credentials" \
     -F "resource=https://help.kusto.windows.net" \
     -F "client_id=AAD_APPLICATION_ID" \
     -F "client_secret=AAD_APPLICATION_KEY"
   

   This code snippet provides you with the bearer token.

   {
     "token_type": "Bearer",
     "expires_in": "3599",
     "ext_expires_in":"3599", 
     "expires_on":"1578439805",
     "not_before":"1578435905",
     "resource":"https://help.kusto.windows.net",
     "access_token":"eyJ0...uXOQ"
   }
   

2. Use the bearer token in your request to the query endpoint.

   curl -d '{"db":"Samples","csl":"print Test=\"Hello, World!\"","properties":"{\"Options\":{\"queryconsistency\":\"strongconsistency\"}}"}"' \
   -H "Accept: application/json" \
   -H "Authorization: Bearer eyJ0...uXOQ" \
   -H "Content-Type: application/json; charset=utf-8" \
   -H "Host: help.kusto.windows.net" \
   -H "x-ms-client-request-id: MyApp.Query;e9f884e4-90f0-404a-8e8b-01d883023bf1" \
   -H "x-ms-user-id: EARTH\davidbg" \
   -H "x-ms-app: MyApp" \
   -X POST https://help.kusto.windows.net/v2/rest/query
   

3. Read the response according to the response status codes.

Set client request properties and query parameters

In the following request body example, the query in the csl field declares two parameters named n and d. The values for those query parameters are specified within the Parameters field under the properties field in the request body. The Options field defines client request properties.

Note

Non-string and non-long parameters must be expressed as KQL literals in string format.

{
    "db": "Samples",
    "csl": "declare query_parameters (n:long, d:dynamic); StormEvents | where State in (d) | top n by StartTime asc",
    "properties": {
        "Options": {
            "maxmemoryconsumptionperiterator": 68719476736,
            "max_memory_consumption_per_query_per_node": 68719476736,
            "servertimeout": "50m"
        },
        "Parameters": {
            "n": 10, "d": "dynamic([\"ATLANTIC SOUTH\"])"
        }
    }
}

For more information, see Supported request properties.

Send show database caching policy command

The following example sends a request to show the Samples database caching policy.

{
    "db": "Samples",
    "csl": ".show database Samples policy caching",
    "properties": {
        "Options": {
            "maxmemoryconsumptionperiterator": 68719476736,
            "max_memory_consumption_per_query_per_node": 68719476736,
            "servertimeout": "50m"
        }
    }
}