You won’t receive a notification if your ESTA has been approved or not by the U.S. Customs and Border
Protection themselves, so you will need to go on the official ESTA website in order to check the
status of your application for any updates you may need.
While it normally takes just a couple of minutes for applications to be reviewed and for a decision
to be taken, sometimes it can take up to three days - so make sure you submit your application well
in advance before your trip.