I posted this on dslreports a few years ago, but since dslreports is gone, I’ll mention it again, in case it’s useful to anyone.
I wrote a utility for checking area code information. You enter the area code, and it will return a list of cities for the area code (not exhaustive, but it gives an idea of the area).
https://www.kilovox.com/utils/check-area-code.html
I have a script that loads the NANPA NPA report into a database to compare information, and check for updates weekly. The updates aren’t automated, but I try to keep up with new area codes so they get added to the database.
It is just a simple form, and simple text output. There are many other websites with area code information, but this is simple and quick. I use it with asterisk to get emails for incoming and outgoing calls, and include the area code information. So if I get a call from an unfamiliar area code, I can see right away where it’s from.