Use API keys for Azure Cognitive Search authentication

Cognitive Search uses API keys as its primary authentication methodology. For inbound requests to the search services, such as requests that create or query an index, API keys are the only authentication option you have. A few outbound request scenarios, particularly those involving indexers, can use Azure Active Directory identities and roles.

API keys are generated when the service created. Passing a valid API key on the request is considered proof that the request is from an authorized client. There are two kinds of keys. Admin keys convey write permissions on the service and also grant rights to query system information. Query keys convey read permissions and can be used by apps to query a specific index.


Authorization for data plane operations using Azure role-based access control (RBAC) is now in preview. You can use this preview capability to supplement or replace API keys with Azure roles for Search.

When connecting to a search service, all requests must include an API key that was generated specifically for your service.

You can view and manage API keys in the Azure portal, or through PowerShell, Azure CLI, or REST API.

Portal page, retrieve settings, keys section

What is an API key?

An API key is a unique string composed of randomly generated numbers and letters that are passed on every request to the search service. The service will accept the request, if both the request itself and the key are valid.

Two types of keys are used to access your search service: admin (read-write) and query (read-only).

Key Description Limits
Admin Grants full rights to all operations, including the ability to manage the service, create and delete indexes, indexers, and data sources.

Two admin keys, referred to as primary and secondary keys in the portal, are generated when the service is created and can be individually regenerated on demand. Having two keys allows you to roll over one key while using the second key for continued access to the service.

Admin keys are only specified in HTTP request headers. You cannot place an admin API key in a URL.
Maximum of 2 per service
Query Grants read-only access to indexes and documents, and are typically distributed to client applications that issue search requests.

Query keys are created on demand.

Query keys can be specified in an HTTP request header for search, suggestion, or lookup operation. Alternatively, you can pass a query key as a parameter on a URL. Depending on how your client application formulates the request, it might be easier to pass the key as a query parameter:

GET /indexes/hotels/docs?search=*&$orderby=lastRenovationDate desc&api-version=2020-06-30&api-key=[query key]
50 per service

Visually, there is no distinction between an admin key or query key. Both keys are strings composed of 32 randomly generated alpha-numeric characters. If you lose track of what type of key is specified in your application, you can check the key values in the portal.


It's considered a poor security practice to pass sensitive data such as an api-key in the request URI. For this reason, Azure Cognitive Search only accepts a query key as an api-key in the query string, and you should avoid doing so unless the contents of your index should be publicly available. As a general rule, we recommend passing your api-key as a request header.

Find existing keys

You can obtain access keys in the portal or through PowerShell, Azure CLI, or REST API.

  1. Sign in to the Azure portal.

  2. List the search services for your subscription.

  3. Select the service and on the Overview page, click Settings >Keys to view admin and query keys.

    Portal page, view settings, keys section

Create query keys

Query keys are used for read-only access to documents within an index for operations targeting a documents collection. Search, filter, and suggestion queries are all operations that take a query key. Any read-only operation that returns system data or object definitions, such as an index definition or indexer status, requires an admin key.

Restricting access and operations in client apps is essential to safeguarding the search assets on your service. Always use a query key rather than an admin key for any query originating from a client app.

  1. Sign in to the Azure portal.

  2. List the search services for your subscription.

  3. Select the service and on the Overview page, click Settings >Keys.

  4. Click Manage query keys.

  5. Use the query key already generated for your service, or create up to 50 new query keys. The default query key is not named, but additional query keys can be named for manageability.

    Create or use a query key


A code example showing query key usage can be found in DotNetHowTo.

Regenerate admin keys

Two admin keys are created for each service so that you can rotate a primary key, using the secondary key for business continuity.

  1. In the Settings >Keys page, copy the secondary key.
  2. For all applications, update the API key settings to use the secondary key.
  3. Regenerate the primary key.
  4. Update all applications to use the new primary key.

If you inadvertently regenerate both keys at the same time, all client requests using those keys will fail with HTTP 403 Forbidden. However, content is not deleted and you are not locked out permanently.

You can still access the service through the portal or programmatically. Management functions are operative through a subscription ID not a service API key, and thus still available even if your API keys are not.

After you create new keys via portal or management layer, access is restored to your content (indexes, indexers, data sources, synonym maps) once you have the new keys and provide those keys on requests.

Secure API keys

Role assignments determine who can read and manage keys. Members of the following roles can view and regenerate keys: Owner, Contributor, Search Service Contributors. The Reader role does not have access to API keys.

Subscription administrators can view and regenerate all API keys. As a precaution, review role assignments to understand who has access to the admin keys.

  1. Navigate to your search service page in Azure portal.
  2. On the left navigation pane, select Access control (IAM), and then select the Role assignments tab.
  3. Set Scope to This resource to view role assignments for your service.

See also