Google Wallet allows you to make payments even without a data connection since it generates a certain number of unique disposable keys on the device which are used by the reader to verify the payment information immediately after they have been transmitted from the Android smartphone via NFC.
Google Wallet can also work offline
Since the unique one-time key is not generated by a server, the transaction can be authorized even offline. However, problems may arise if you remain offline for a long period, as the code reserve may run out and in this case the cards in Google Wallet may no longer be available.
Since it is unlikely that NFC payments will be made in places where there may be no connection for long periods, we can say that there is no point in worrying.
Google points out that connecting to the Internet every couple of days will keep the code reserve full, which will allow you to use Google Wallet practically all the time.
