Every gift card includes a unique number in the form of a barcode, magnetic stripe, encoded chip, or even something as simple as a plain human readable number. It is that number which is activated, or “loaded”, with the proper dollar amount. This is done in the gift card transaction system database.
Activating or loading a gift card implies that the card is somehow changed to reflect the activation process, but this is not the case. The card is presented to the system (swiped or read) and the unique card number is confirmed in a database. The dollar amount to load on the card is input to the database and is associated with the unique card number within the database. The card is now activated or loaded. Absolutely no change has been made to the card itself.
When the activated gift card is presented for redemption, the unique number is again read into the database. The associated card value is then retrieved from that database, the spent amount is deducted from this amount, and this new lower value is then stored back in the database.