> ## Documentation Index
> Fetch the complete documentation index at: https://docs-dev.auth0-mintlify.app/llms.txt
> Use this file to discover all available pages before exploring further.

# Application Access to APIs: Client Grants

> Learn about Client Grants

In Auth0, you can control how applications access your APIs using [application API access policies](/docs/get-started/apis/api-access-policies-for-applications) and client grants.

A client grant provides fine-grained application access to an API. It associates:

* An API identified by its `audience` or unique identifier.
* An application identified by its `client_id`.
* A list of permissions such as scopes and/or `authorization_details_types` that the application is allowed to request for the specified audience.

To learn more about the list of attributes you can define in a client grant, read [Client grant attributes](#client-grant-attributes). To learn how to define and manage client grants, read [Create client grant](#create-client-grant).

## Application API access policies and client grants

When you configure an API's [application access policy](/docs/get-started/apis/api-access-policies-for-applications) to `require_client_grant`, only applications with a client grant defined can get an access token for the API. The client grant establishes the maximum permissions an application can request from the API by following the least privilege principle approach. As a result, Auth0 recommends using `require_client_grant` when configuring an API’s application access policy.

### Example: Social Media API

To illustrate how client grants follow the least privilege principle approach, say you have a Social Media API with the permissions: `read:posts`, `write:posts`, `read:friends`, and `delete:posts`. You create an application and define a client grant with the permissions: `read:posts` and `write:posts`.

This client grant now serves as a hard ceiling. Even though the Social Media API has other permissions, your application can never request or be granted `read:friends` or `delete:posts`.

## User-delegated access vs. client access

In user and client access, client grants define the final set of permissions that control an application’s access to an API. The client grant’s `subject_type` attribute determines the type of application access allowed for an API.

An application can have up to two client grants for a single API:

* When you set `subject_type` to `client`, you define its machine-to-machine permissions.
* When you set `subject_type` to `user`, you define its permissions to act on the user’s behalf.

The following table explains how client grants control application access to APIs based on the access type flow:

| Access type                                          | subject\_type attribute         | Description                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
| ---------------------------------------------------- | ------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Client credential access (Machine-to-machine access) | Set `subject_type` to `client`. | The client grant directly authorizes the application to access the API on its own behalf instead of the end user’s behalf. The permissions you define in the client grant are the ones the application is authorized to receive in the access token.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
| User-delegated access                                | Set `subject_type` to `user`.   | The client grant defines the maximum permissions the application can request from the API. The final permissions in the access token issued to the application on the user’s behalf are the intersection of the permissions:<br /><ul><li>Requested by the application</li><li>Allowed by the client grant</li><li>Allowed by [Role-Based Access Control policies](/docs/manage-users/access-control/rbac) for the user</li><li>[Consented to by the end user](/docs/get-started/applications/third-party-applications/user-consent-and-third-party-applications), if applicable.</li></ul><br />To learn more about user-delegated access flows, read [Authentication and Authorization Flows](/docs/get-started/authentication-and-authorization-flow). User-delegated access flows do not include the Client Credentials Flow. |

<Callout icon="file-lines" color="#0EA5E9" iconType="regular">
  You can modify the final scopes granted by the authorization server to the application or user using [Actions](/docs/customize/actions).
</Callout>

## Client grant attributes

A client grant has several attributes that you can define to configure application access to APIs using the Auth0 Management API:

| Attribute                     | Description                                                                                                                                                                                                                                                                                                                                                                                                                                     |
| ----------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `id`                          | Unique identifier of the client grant.                                                                                                                                                                                                                                                                                                                                                                                                          |
| `audience`                    | Unique identifier of the API the client grant is for.                                                                                                                                                                                                                                                                                                                                                                                           |
| `client_id`                   | The unique ID of the application that is being granted access.                                                                                                                                                                                                                                                                                                                                                                                  |
| `scopes`                      | An array of strings representing the permissions the application can request.                                                                                                                                                                                                                                                                                                                                                                   |
| `authorization_details_types` | An array of strings representing rich authorization data types that the application can request. This attribute can only be specified for user-delegated access flows.                                                                                                                                                                                                                                                                          |
| `subject_type`                | The type of application access the client grant allows for:<br /><ul><li>`user`: used for user-delegated access, which corresponds to all flows that generate a token associated with an end user.</li><li>`client`: used for machine access, which corresponds to the Client Credentials Flow.</li></ul>                                                                                                                                       |
| `allow_all_scopes`            | Boolean. Indicates if all scopes defined on the API are allowed for the application. Future defined scopes, for the API, are automatically permitted.                                                                                                                                                                                                                                                                                           |
| `organization_usage`          | Determines how the application may use organizations when accessing the API via the Client Credentials Flow. Possible values are: `deny`, `allow`, or `require`.<br /><br />To learn more about the Organization settings, read [Organizations for M2M Applications: Define Organization Behavior](/docs/manage-users/organizations/organizations-for-m2m-applications/configure-your-application-for-m2m-access#define-organization-behavior). |
| `allow_any_organization`      | Determines whether the application can access any organization when using the Client Credentials Flow.<br /><br />To learn more about the Organization settings, read [Organizations for M2M Applications: Define Organization Behavior](/docs/manage-users/organizations/organizations-for-m2m-applications/configure-your-application-for-m2m-access#define-organization-behavior).                                                           |

## Configure client grants

You can configure client grants using the <Tooltip tip="Auth0 Dashboard: Auth0's main product to configure your services." cta="View Glossary" href="/docs/glossary?term=Auth0+Dashboard">Auth0 Dashboard</Tooltip> or the <Tooltip tip="Management API: A product to allow customers to perform administrative tasks." cta="View Glossary" href="/docs/glossary?term=Management+API">Management API</Tooltip>.

<Tabs>
  <Tab title="Auth0 Dashboard">
    To configure client grants using the Auth0 Dashboard:

    1. Navigate to [Dashboard >  Applications](https://manage.auth0.com/#/applications).
    2. Select the **Application** you want to configure.
    3. Select the **APIs** tab.
    4. Select **Edit** to authorize **User-Delegated Access**, **Client Access**, or both.

    <Callout icon="file-lines" color="#0EA5E9" iconType="regular">
      For application-level authorization settings to take effect, you must set API Access Policy to Allow via client-grant. To learn more read, [API Access Policies for Applications](/docs/get-started/apis/api-access-policies-for-applications).
    </Callout>

    * Configure the **User-Delegated Access Authorization** to **Unauthorized**, **Authorized**, or **All**.
      * **Unauthorized**: No permission allowed.
      * **Authorized**: Select desired permissions.
      * **All**: Include all existing and future permissions.
    * Configure the **Client Credential Access Authorization** to **Unauthorized**, **Authorized**, or **All**.
      * **Unauthorized**: No permission allowed.
      * **Authorized**: Select desired permissions.
      * **All**: Include all existing and future permissions.

    5. Select **Save** to save the **Application's API** settings.
  </Tab>

  <Tab title="Management API">
    To configure client grants, use the `/client-grants` endpoint.

    **Create client grant**

    To create a new client grant, make a [`POST`](https://auth0.com/docs/api/management/v2/client-grants/post-client-grants) request to the `/client-grants` endpoint:

    ```bash lines theme={null}
    curl --location 'https://{yourDomain}/api/v2/client-grants' \
    --header 'Content-Type: application/json' \
    --header 'Authorization: Bearer {YOUR_MANAGEMENT_API_TOKEN}' \
    --data '{
        "client_id": "{CLIENT_ID}",
        "audience": "https://api.my-service.com",
        "scope": [
            "read:item"
        ],
        "authorization_details_types":["payment"],
        "subject_type": "user"
    }'
    ```

    **Update client grant**

    To update an existing client grant, make a [`PATCH`](https://auth0.com/docs/api/management/v2/client-grants/patch-client-grants-by-id) request to `/client-grants/{id}`:

    ```bash lines theme={null}
    curl --location --request PATCH 'https://{yourDomain}/api/v2/client-grants/{CLIENT_GRANT_ID}' \
    --header 'Content-Type: application/json' \
    --header 'Authorization: Bearer {YOUR_MANAGEMENT_API_TOKEN}' \
    --data '{
        "scope": [
            "read:item",
            "update:item"
        ],
        "authorization_details_types":["payment", "credits_transfer"]
    }'
    ```

    **Delete client grant**

    To delete a client grant, make a [`DELETE`](https://auth0.com/docs/api/management/v2/client-grants/delete-client-grants-by-id) request to `/client-grants/{id}`:

    ```bash lines theme={null}
    curl --location --request DELETE 'https://{yourDomain}/api/v2/client-grants/{CLIENT_GRANT_ID}' \
    --header 'Authorization: Bearer {YOUR_MANAGEMENT_API_TOKEN}'
    ```

    **Retrieve client grants**

    You can also query and paginate through the `client-grants` collections by using parameters like `client_id`, `audience`, or `subject_type`:

    ```bash lines theme={null}
    curl --request GET \
    --url 'https://{yourDomain}/api/v2/client-grants?subject_type=user&audience=https%3A%2F%2Fapi.my-service.com' \
    --header 'Authorization: Bearer {YOUR_MANAGEMENT_API_TOKEN}' \
    --header 'Accept: application/json'
    ```
  </Tab>
</Tabs>

## Default permissions for third-party applications

[Third-party applications](/docs/get-started/applications/third-party-applications) always require an explicit client grant to access any API, even when the API's [access policy](/docs/get-started/apis/api-access-policies-for-applications) is set to **Allow All**. To simplify management when you have many third-party applications or use [Dynamic Client Registration](/docs/get-started/applications/dynamic-client-registration), configure default permissions that apply to all third-party applications automatically.

A default third-party client grant uses the `default_for` attribute instead of a `client_id`. You can also define per-application permissions by creating a client grant with a specific `client_id`. When both exist for the same API, per-application permissions take precedence.

<Callout icon="file-lines" color="#0EA5E9" iconType="regular">
  System APIs (the Management API, My Account API, and others) do not support default third-party client grants. Third-party applications cannot be granted access to system APIs.
</Callout>

The `default_for` and `client_id` attributes are mutually exclusive. Each client grant must specify exactly one of them.

To learn how to configure API access policies for third-party applications, read [Configure Third-Party Applications](/docs/get-started/applications/third-party-applications/configure-third-party-applications#configure-api-access-policies).

## Learn more

* [API Access Policies for Applications](/docs/get-started/apis/api-access-policies-for-applications)
* [Application Grant Types](/docs/get-started/applications/application-grant-types)
* [Third-Party Applications](/docs/get-started/applications/third-party-applications)
* [Configure Third-Party Applications](/docs/get-started/applications/third-party-applications/configure-third-party-applications)