WordPress REST API - This will return variables of 2 or more

get_wp_rest_api.php

add_action( 'rest_api_init', function () {
	register_rest_route(
		'testapi/v1', '/getvars/(?P<var1>\d+)/(?P<var2>\d+)', array(
			'methods' 	=> 'GET',
			'callback' 	=> 'wp_restapi_getvars',
			)
		);
	}
); 

function wp_restapi_getvars( $data ) {
	echo 'This is var1:' . $data['var1'] . '<br>'; 
	echo 'This is var2:' . $data['var2'] . '<br>'; 
}