I had the same situation and contacted the authorities and they replied by saying the ESTA is valid until the end of the day of the expiration date. So you can travel on the day of your ESTA expiry:
“Yes, the ESTA would be valid through 11:59 PM on its expiration date. You can use the ESTA if it will be valid for your date of travel and date of arrival. Note that if your travel or processing through immigration is delayed that this could cause problems if your ESTA will become expired during the delay. We hope this helps to answer your question.”
You have an edge case. Typically, it is OK for the ESTA to expire during your visit. From US Customs and Border Protection website:
Does my ESTA need to be valid for my entire stay in the United States?
No, An ESTA is only required to be valid on the day you enter the
United States. The ESTA does not need to be valid for the entire time
a traveler is in the U.S.. If the ESTA expires while you are in the
U.S., it will not affect your admissibility or the amount of time you
are permitted to remain in the U.S. If an ESTA travel authorization
expires before the traveler leaves the United States, the traveler is
not required to apply for another. The traveler will need to apply for
a new travel authorization through ESTA, however, for future travel.
You should either contact the nearest USA consulate and get a definitive on if it is considered valid for the day of expiration or not or, as most ESTA applications are approved within minutes, you could simply renew your ESTA. An ESTA may be renewed prior to the previous one expiring.
On the renewal front a little Googling turned up:
Please plan to apply at least 72 hours before you travel to allow time
for ESTA processing.
On UsaEmbassy.gov. That is 3 days, so you are just about on the right side of the equation, depending on when your flight is. Most likely, since you already had an ESTA, you’ll be approved automatically in minutes.
Credit:stackoverflow.com‘