I can't load the site, so I'm not sure exactly what it's offering, but I'm also not sure what you mean by a regex for zipcodes. Surely it'd be simpler, quicker, and more maintainable just to match /(\d{5})/ and filter out invalid codes after the fact?

(Edit: If you want the full ZIP+4 where it's given, you can add (\-\d{4})? as a term in the regex, and you can validate them the same way. USPS also offers an API for validating address information; it's been some years since I used it, and I recall it being somewhat recondite in the fashion of most .gov APIs, but it's there and it works.)

Edit again: OK, the site loaded. It looks like a tool for generating regexes via machine learning techniques to match highly complex targets. From a purely technical perspective, that sounds really neat -- but from a maintainability perspective, it sounds like even more of a nightmare than complex regexes usually are.

The site has gone down, once for a power outrage and another time cause the traffic peak... I think the problem are solved now. :-)

> power outrage

I like that!

Auch! my fault, it sounds like but it is not :-)

The GeoNames Country Information table has a "Postal Code Regex" column that you might find interesting: http://download.geonames.org/export/dump/countryInfo.txt

Some of those regexes are terrifying. Granted that I'm not sure there is any better alternative for extracting structured address information from an unstructured source, but...