WordPress at a glance
filter is not described

rest_pre_insert_user filter-hook . WP 4.7.0

Filters user data before insertion via the REST API.

Usage

add_filter( 'rest_pre_insert_user', 'filter_function_name_5704', 10, 2 );
function filter_function_name_5704( $prepared_user, $request ){
	// filter...

	return $prepared_user;
}
$prepared_user(object)
User object.
$request(WP_REST_Request)
Request object.

Where the hook is called

WP_REST_Users_Controller::prepare_item_for_database()
rest_pre_insert_user
wp-includes/rest-api/endpoints/class-wp-rest-users-controller.php 1048
return apply_filters( 'rest_pre_insert_user', $prepared_user, $request );

Where the hook is used (in WP core)

Does not used.