8,200 in Germany is way too low, and I'll add some fun facts.
According to Wikipedia 30,000 of the theoretical 98,901 are currently in use. The number of people per postcode does vary a lot, from zero (no one lives in a company that has its own postcode) to none living in a demolished village of Billmuthausen (right on the inner-German border) or the two people living in a district that had no postcode until the problem was fixed in 2015. Yes, they forgot Gutsbezirk Reinhardswald (a quarter the size of Frankfurt/Main) which is almost all forest but has a forester hut with two people. There are even four Austrian villages that also have a German postcode in addition to their Austrian one, and a swiss one. There are even still four-digit postcodes with no five-digit update in use: Feldpost, the Germna army postal service.
Some larger retail stores in Germany ask you for your postcode during checkout, presumably to learn a bit about their customer base. I don't mind telling them mine, there are about 16K people with the same postcode. But I'm pretty sure I would not tell them if I was one of the two forest rangers in Reinhardswald. (And yes, I do pay cash whenever I can.)
Interesting, is the German postcode not used for transaction validation? I know the American payment processors definitely use ZIP codes for validation - see anecdote 1.
That said, there are definitely situations where the payment processors don't require the ZIP code - see anecdote 2.
Anecdote 1: When I worked in food service as a kid, I used card terminals that connected directly to a phone line. I remember a couple of times when I entered the ZIP code incorrectly - the card terminal would print out a receipt with an angry message saying the transaction got rejected. So, I know they were using the ZIP code to validate the transaction.
Anecdote 2: With those same card terminals, you could skip the ZIP code and it would run the transaction as usual. But, my manager always told me not to do that. Maybe I never asked him why, or maybe I forgot his answer. Regardless, I don't remember why we he required us to enter the ZIP code, even when it didn't seem to be necessary.
ZIP codes are used as a weak "something you know" factor in payment card processing.
The card is (for card-present transactions) "something you have". And the ZIP complements that. ZIP code is optional, but the merchant gets a data integrity score back from the network ("AVS/address verification service response", from no match to full match), and can accept/decline the txn at their discretion.
Because it's optional and at merchant discretion, all it really does is give the merchant some additional ammunition when disputing a chargeback. And of course to build a demographic database.
The answer to anecdote 2 is probably that if the seller chooses to skip validation measures on the transaction, then they become liable in the event the transaction is deemed fraudulent.
> is the German postcode not used for transaction validation?
No. The only time I have ever been asked for a post code was when a petrol pump in the US demanded my zip code. I have no idea what it meant, I just put some random zip code for the general area I was in and it was accepted. I've never been asked for my post code in Europe; I can't speak for the whole of Europe though, just UK, Spain, Ireland, Portugal, France, Belgium, Netherlands, Italy, Germany, Poland, Denmark, Sweden, Norway.
It's very interesting to know that postal code verification isn't the global M.O... I've been curious about this for a while and you've provided some valuable context.
FWIW: the pump was asking for the ZIP code of the billing address you have on file with your bank. If I typed in a random ZIP code, my card would get declined. I'm pleasantly surprised someone actually thought to handle the "foreign address" case, even if it's silly that the machine forced you to provide a ZIP code in the first place. That's how low my bar is for payment processing networks, I guess.
This might help explain in-part the discrepancy. Perplexity.ai[1] also says 8,200 German postal codes. I set Claude 3.5 Sonnet in the LLM settings on Perplexity but it looks like it might use a ChatGPT model for the initial search of sources? At least we can see what it is sourcing to fetch the value of 8,200. Interestingly, asking Claude 3.5 Sonnet directly at claude.ai returned 16,000.[2]
1. The first digit represents one of 10 postal regions.
2. The second digit typically represents a sub-region within that area.
3. The last three digits identify specific delivery areas or post offices.
It's worth noting that the exact number can fluctuate slightly over time due to administrative changes, urban development, or postal service reorganization. However, 16,000 is a good approximation for the total number of German postal codes.
Would you like more information about how the German postal code system works or its history?"
I felt your reply was too harsh, but after few moments I realized that I instinctively think the same I treat any output from ChatGpt as garbage until checked in other sources. So effectively, not worth looking there in the first place.
I think that it's often easier to verify an answer than to find an answer with nothing to go on, so perhaps not entirely garbage but certainly not reliable.
