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

> Learn how to use the Write Hook with the Delegated Administration Extension.

# Delegated Administration: Write Hook

The Write Hook, which runs anytime you create or update a user, allows you to do things like:

* Changing the user's password
* Changing the user's email address
* Updating the user's profile

You can also use the Write Hook to automatically set default values for newly-created users. For example, you might want to automatically assign a user to the same group, department, or vendor as the ones to which you've been assigned.

<Warning>
  Auth0 only supports user creation with Database Connections.
</Warning>

## Hook contract

* **ctx**: Context object.

  * **request.originalUser**: Current user's values where the **payload** is the new set of fields. Only available when the method is **update**.
  * **payload**: Payload object

    * **memberships**: Array of memberships that were selected in the UI when creating the user.
    * **email**: Email address of the user.
    * **password**: Password of the user.
    * **connection**: Name of the database connection.
    * **app\_metadata**: Data that's included if a Custom Field being modified is saved in `app_metadata`.
    * **user\_metadata**: Data that's included if a Custom Field being modified is saved in `user_metadata`.
  * **userFields**: User fields array (if specified in the settings query)
  * **method**: Either **create** or **update** depending on whether this is being called as a result of a create or an update call.
* **callback(error, user)**: Callback to which you can return an error and the user object that should be sent to 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>.

For more information about **userFields**, read [Delegated Administration: Settings Query Hook](/docs/customize/extensions/delegated-administration-extension/delegated-administration-hooks/delegated-administration-settings-query-hook).

## Sample use

Kelly manages the Finance department. When she creates users, these users should be assigned as members of the Finance department.

```javascript lines expandable theme={null}
function(ctx, callback) {
  var newProfile = {
    email: ctx.payload.email,
    password: ctx.payload.password,
    connection: ctx.payload.connection,
    user_metadata: ctx.payload.user_metadata,
    app_metadata: {
      department: ctx.payload.memberships && ctx.payload.memberships[0],
      ...ctx.payload.app_metadata
    }
  };

  if (!ctx.payload.memberships || ctx.payload.memberships.length === 0) {
    return callback(new Error('The user must be created within a department.'));
  }

  // Get the department from the current user's metadata.
  var currentDepartment = ctx.request.user.app_metadata && ctx.request.user.app_metadata.department;
  if (!currentDepartment || !currentDepartment.length) {
    return callback(new Error('The current user is not part of any department.'));
  }

  // If you're not in the IT department, you can only create users within your own department.
  // IT can create users in all departments.
  if (currentDepartment !== 'IT' && ctx.payload.memberships[0] !== currentDepartment) {
    return callback(new Error('You can only create users within your own department.'));
  }

  if (ctx.method === 'update') {
    // If updating, only set the fields we need to send
    Object.keys(newProfile).forEach(function(key) {
      if (newProfile[key] === ctx.request.originalUser[key]) delete newProfile[key];
    });
  }

  // This is the payload that will be sent to API v2. You have full control over how the user is created in API v2.
  return callback(null, newProfile);
}
```

## Learn more

* [Delegated Administration: Access Hook](/docs/customize/extensions/delegated-administration-extension/delegated-administration-hooks/delegated-administration-access-hook)
* [Delegated Administration: Filter Hook](/docs/customize/extensions/delegated-administration-extension/delegated-administration-hooks/delegated-administration-filter-hook)
* [Delegated Administration: Memberships Query Hook](/docs/customize/extensions/delegated-administration-extension/delegated-administration-hooks/delegated-administration-memberships-query-hook)
* [Delegated Administration: Settings Query Hook](/docs/customize/extensions/delegated-administration-extension/delegated-administration-hooks/delegated-administration-settings-query-hook)