US zip codes are authorized and assigned by the USPS, so by definition they are proprietary. However, the data itself (once it is obtained) is freely redistributable (in raw form).

The barrier is that the official source of zip code data, National Five-Digit ZIP Code and Post Office Directory, is copyrighted[0], and there is work in extracting the data from it.

The nice thing is that US copyright law limits the protection for "facts" [1]. The selection and arrangement of facts can be copyrighted, but not the underlying facts themselves. So it's perfectly legal in the US to take the zip code data and distribute it, just not in the original form from the National Five-Digit ZIP Code and Post Office Directory.

As for other countries than the US, it would depend on their local laws.

[0] - http://pe.usps.com/Archive/HTML/DMMArchive0810/G013.htm

[1] - https://en.wikipedia.org/wiki/Copyright_law_of_the_United_St...

For anyone else wondering why isn't National Five-Digit ZIP Code and Post Office Directory in public domain like every other work of the US government:

>Works by certain independent agencies, corporations and federal subsidiaries may not be considered "government works" and may, therefore, be copyrightable. For instance, material produced by the United States Postal Service are typically subject to normal copyright.

https://en.wikipedia.org/wiki/Copyright_status_of_work_by_th...

Thank you for running ZipLocate for free, I admire this.

On a similar note, do you (or anyone else) know how to get data about the parcels/property sizes in the US (e.g: I want to check if address X is over 10k square feet)? Are there any open sets from which it would be possible to compile this dataset, or the only way is to go to Maponics etc and pay (but still, where do Maponics got this data from)? I needed this for my last project - at the time I used Zillow API (http://www.zillow.com/howto/api/GetDeepSearchResults.htm) but it was rate limited and had data for only about 50% of addresses I queried.

I don't think PAF (which is Australia's postal data) is included in this announcement.

No one should be using PAF to geocode, anyway.

GNAF includes addresses derived from the PAF. The vast majority ie over 90% are matched to jurisdictional addresses and just increase the confidence value. Where they don't match and there are more than 5 of them they are included as street level addresses. Only jurisdictional addresses have cadastral level geocodes.

Thanks, learning something new every day.