Credit Card Numbers

Every since I found out that the first digits of any credit card denote the issuer identifier (i.e., folks can tell who issued a credit card and what type it is just from the first digit or two) I’ve been annoyed almost each time I have to input credit card information on the web. Any decent credit card system knows that if a sixteen digit credit card number starts with 4, it’s a Visa. And yet, each time anyone buys anything on the web, they must select "Visa" from the drop-down box. On a certain level we all know this; People in stores and restaurants never have to select the type of card before swiping.

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When I’m feeling generous, I imagine this is so that the credit card companies can give an extra reminder that they only accept certain credit cards — not being able to select a card type in an "essential" input field constrained to multiple choices is a pretty strong reminder.

When I’m feeling less generous, I suspect it might be so that the companies can subtly remind us that they have their own brand credit cards that we might like to acquire.

10 Replies to “Credit Card Numbers”

  1. Actually, I always assumed it was just for redundancy, like entering your email address twice.  It’s a way of helping people make sure they’re using the card they intended to use (in the restaurant you  physically see the card, so that provides the redundacy check there).

  2. Just add “Miles & More Frequent Flyer card” and to your list and check if your logic still applies ;)

    Your logic works for some categories of Credit Card, but definitely not for any kind of number-based payment method.

    – another reason is that the merchant doesn’t want to implement this logic which is prone to change – you want your Payment Service Provider to do this.

  3. Just add “Miles & More Frequent Flyer card” and to your list and check if your logic still applies ;) – Yes, you can pay with it, but in Miles ! –

    Your logic works for some categories of Credit Card, but definitely not for any kind of number-based payment method.

    – another reason is that the merchant doesn’t want to implement this logic which is prone to change – you want your Payment Service Provider to do this.

  4. Ugh, yeah I hate that. Coincidentally, I’m currently in the process of writing another payment gateway at the company I work for. This card processor requires a “cardType” field, as I’ve seen on others, and reading your post today makes me think that maybe those online stores and such ask so they can dump your form fields right into the transaction data.

    As for ours, I’m just bringing in a bit of logic I previously wrote to determine the card type from the number, and then passing that along.

  5. Re verifying for you that you’re using the correct card, a nice alternative I’ve seen implemented very occasionally is that the customer inputs the card number and then is told that it’s Visa or Mastercard or whatever.

  6. I just bought something through Paypal, and was really thrilled (after reading this post) that it automatically picked the card type! It’s actually pretty cool–it starts off with 4 logos under “Card Type” and three of them disappear when you type in that first 4.

  7. I also have seen a few Web stores that will select the card type automatically after you input the first few digits. I always sort of assumed that making you pick the card type was a sort of poor man’s checksum: did you just type in a random string of numbers that happens to be a valid card number, or is it actually a Visa?

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