>>No idea how if your zip codes can start with a zero,
>>but that was relatively easy to fix as our zip codes always have 5 digits.
>>
>>Phone # length on the other hand might range a lot, checking
>>for length, area code and "probable mobile code" was challenging.
>
>The probable mobile code may work in Europe - here it's 064, 060, 0677, 064 and such, I've seen 09x in Croatia, and ISTR there were such prefixes in Belgium. In the US, however, the mobile providers have local area codes, so your landline and your mobile have the same area code. Really hard to guess which is which, looking at the number. There's probably some lookup table somewhere, from which you can find that out, but we never bothered, as it's probably changing from year to year and it may also cost some to get, and would require maintenance for... not much of a gain at all.

Used to be similar here, at start you could even bank on which net callee was:
0171:D!, 0172:D2, 0177:E
but when these "area" codes were full, new ones did not always separate.
Was nice, as calling into different Net was cost intesnive in the first years.

Then taking your # to different providers nuked that -
no problem, as nowadays allnet flat often is standard.

Today you can map # to IP phone services - including area codes,
as long as you have a physical adress there when starting the contract.

Since fudging phone numbers is stopped for calls from abroad now
due to rising count of phone scam calls. that is a tug of war now...