JPostal is a free, open-source, Java library that allows you to add sophisticated ZIP code validation to your J2SE and Java EE applications. Using JPostal, your application can easily compute the answer to questions such as: What city and state correspond to zip code 85050 ? (Phoenix, AZ) Is 43551 the zip code for Perrysburg, OH ? (Yes) And does the US Postal Service recognize any other cities in that zip code? (No) Using these capabilities, it's easy to validate city, state, and zip code combinations within your application. You can also auto-populate city and state fields when a user enters a ZIP code. JPostal is designed for high performance: validations take less than 1ms. It provides a variety of data access strategies that make different space and time tradeoffs, allowing you to choose the one that's most suitable for your application. The latest release includes US Postal Service data that are current as of March 2009.

I realize it's a long shot, but anyone know of a similar tool that works for Canadian postal codes?

nice tool

The title should be: JPostal supports _US_-ZIP code validation in Java Apps. Where have the editors gone?

The title should be:

JPostal supports _US_-ZIP code validation in Java Apps.

Where have the editors gone?

Indeed, although this is very useful by itself, these days a lot of orders tend to be international orders. Support for other countries (I would say at least Canada, Australia, Europe and perhaps Japan) would be very nice.

ZIP codes refer specifically to US postal codes, so putting "US ZIP codes" in the title would be redundant.

Maybe in your country. But not in mine (Switzerland). Both 'postcode'/'postal code' (British English), and 'zip code' (American English) mean the same thing. If not, then 'color' would only apply to colors within the USA?

I'm sorry, you are right: The word 'zipcode' really only applies to US 'postal codes'. I didn't know. To my defense, my dictionary didn't know either...

I'm sorry, you are right: The word 'zipcode' really only applies to US 'postal codes'. I didn't know. To my defense, my dictionary didn't know either...

And I think about 99% of the international readers don't know zipcode really only refers to US postal codes. Most will think it's just a British vs US English thingy. So even though technically correct, it would have been wise to specifically mention "US only". And of course the fact should be mentioned that the library has a plugin option for other countries, so people can provide the implementation for their country... The "US" is not as nationally focus as it used to be. Right? ;-)

If not, then 'color' would only apply to colors within the USA?

Yup. England uses 'colours' :)

If not, then 'color' would only apply to colors within the USA?

Yup. England uses 'colours' :)

Yeah, but only when you're in the neighbourhood. :P

My zip code is the first example...85050.

Note the capitalization in ZIP used in the software description. ZIP Code is a trademark of the US Postal Service and is an acronym for zone improvement plan. It has been a very successful acronym that appears to have gotte into the vernacular, usually as zip code or zipcode (uncaptitalized) and become a generic term outside of the US for postal code.

The Computer Server Side (lets not insult waitstaff) is a nice Internet Web Site (lets not insult spiders either).