A reward code is the digital version of a full paper card. When a customer reaches the target, the scheme issues a short string of letters and numbers tied to that customer and that reward. It is proof that the reward was earned, and it stays on record until the reward is handed over. A good code is short enough to read aloud across a counter and avoids characters that look alike, such as zero and the letter O, or one and a capital I, so nobody argues about what it says.
The point of a code is that neither side has to remember anything. The customer does not need to keep a full card safe until their next visit, and the person at the till does not need to trust a story about a card left at home.
In practice
A cafe with a nine-stamp card issues 64 reward codes in a month. Staff hand over the free coffee on the spot for 58 of them. Six customers fill their card on a busy morning and ask to save the reward, three because they had already ordered and two because they wanted to bring a friend. The sixth simply forgot. Over the next month five of those six come back, give their name, and claim their coffee from the code on file. One code is still waiting at the end of the second month, which is a reminder to mention it next time that face appears.
That is a redemption rate of 63 out of 64 within two months, which tells the owner the reward is wanted and the staff are offering it.
In Counter Club
The code is six characters, with look-alike characters left out. It appears next to the Stamp button as "Reward earned" at the moment the card fills, and in the Rewards waiting column on the member's row. Press Mark used beside the code when you hand the reward over, so it cannot be claimed twice. See reward codes.