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 below for the request headers and body to include.

Request headers

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

Standard header	Description	Required/Optional
Accept	Set to application/json	Required
Accept-Encoding	Supported encodings are gzip and deflate	Optional
Authorization	See authentication	Required
Connection	We recommend that you enable Keep-Alive	Optional
Content-Length	We recommend that you specify the request body length when known	Optional
Content-Type	Set to application/json with charset=utf-8	Required
Expect	Can be set to 100-Continue	Optional
Host	Set to 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 otherwise indicated, these headers are used for telemetry purposes only, and have no functionality impact.

All headers are optional. We recommend that you specify the x-ms-client-request-id custom header. In some scenarios, such as canceling a running query, this header is required because 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	Same 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, forces the request to run in read-only mode, preventing it from making long-lasting changes

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	Text of the query or management command to execute	Required
db	Name of the database in scope that is the target of the query or management command	Optional for some management commands. Required for other commands and all queries.
properties	Provides request properties that modify how the request is processed and its results. For more information, see Request properties	Optional

GET query parameters

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

Body

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

Examples

This 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\"}"
}

This example shows how to create a request that sends the query above, 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 having set 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 will provide 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 this specification.

Set client request properties and query parameters

In the following example body, 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.