Can I access my Store via the API whilst updates are being installed ?
Whenever you update plugins or WordPress itself your website is taken offline temporarily – visitors to the site will see the standard message that the site is “Briefly unavailable for scheduled maintenance. Check back in a minute”.
API requests to the site will also fail with an HTTP response code of 503 (Service Unavailable). Once the updates are finished installing you will be able to make API requests again successfully.