The "Fast Lane" Answer
Address validation is the process of checking a mailing address against an authoritative database to see if the address is real. (This process is also know as address verification.) If there's a matching address on file in the database, the address validates, meaning it's a real and bona fide address. Addresses that find no match in the database are marked invalid, meaning the address either doesn't exist or isn't registered.
In the United States, the authoritative database for address lookups is the USPS. Most countries around the world have their own respective database against which addresses can be validated. Though address formats vary nation to nation, the process is largely the same: Check to see if the address is on file. If it is, the address is valid. If it is not, the address is invalid.
It's as simple as that. Valid addresses are real addresses.
The "Scenic Route" Answer
Address validation can also be a little more complicated than that. There's a lot that has to be done before an address can be validated, and there's a lot of reasons that a real address might not validate. To understand details like this, it's best to start at the beginning.
The process, start to finish
Before an address validation provider like SmartyStreets (that's us; look at the top of the page if you don't believe it) can validate an address, it has to go through some cleanup first, which usually involves standardization and parsing.
Standardization of an address is the first step: this is where a CASS-certified provider cleans up an address—including reformatting the address to USPS standards, filling in missing data, and checking for spelling errors—so that the address will look like the ones that are in the database.
Standardizing does a lot. The first thing it does is match the formatting of the mailing authority (the USPS in the United States). "Street" becomes "St.", "Avenue" becomes "Ave.", and so on. States or provinces also receive proper abbreviations. Standardizing can even do things like correct misspelled words and fill gaps in the data, such as missing ZIP Codes, street suffixes, and so on. Much of that, however, requires the aid of parsing.
Parsing, in general terms, is when a program tries to analyze the syntax of data input by a user, so that it can identify the parts that make it up. In the case of address parsing, it means breaking down an address into its parts (like city, state, ZIP, etc.), and then labeling it. Different versions of parsing have different levels of accuracy—and different levels of functionality—but the good ones can compare an incomplete, misspelled, or incorrectly formatted address against the database, fixing what's wrong and filling in what's missing.
Once the address is in tip-top shape, it's validated by looking for its twin in the database. If there's a match, the address is valid. If not, it's invalid.
If the answer is "no"...
Just because an address didn't validate, however, doesn't mean the address is not real. There are multiple reasons an address might come up as invalid. Here are a few:
- Imaginary address: The address is fake, hypothetical, no longer exists, or does not yet exist. Making up a number for a house on your street would have this effect, as would using the address of a building torn down six months ago.
- Incorrect address: Sometimes the entered address is so poorly spelled/formatted that it can't be accurately corrected. Or the wrong information is given, such as incorrect street name or house number.
- Address not occupied: Perhaps a building is new or vacant. Either way, if no one's there to receive mail, the address won't be listed in the database, so it won't validate.
- Address not registered: New buildings, new occupants, occupants that don't want/need to receive mail—all are examples of an address not being registered yet/anymore with the USPS. If they haven't registered, they're not in the system, so the address is considered invalid.
Address validation providers often complement their validation services with additional data and features. These can range from providing the census information and climate statistics of the area the addresses come from, to providing the geocode coordinates of the address. Here at SmartyStreets, for example, we focus primarily on address validation and geocodes, both US and international. Then we supplement that focus with features designed to make our system easier to use.
First of all, we offer batch processing in two formats for anyone eager to process large quantities all at once. Our service is also fast enough to make you question your own sanity. We support API integration, and a host of web plug-ins. We also offer ZIP+4 accuracy, ZIP Code classification, time zone information, and much more data about the address.
If address validation is what you're looking for...
You may have stumbled into this article simply curious about the topic. But odds are, you came searching with a purpose. If you need address validation, go ahead and try it right now for free. If you need more help, we'd be happy to help, that is, we're just so helpful that we can't help it. Go ahead and call us (it's nice to do business with a human being every now and again, isn't it?), or chat with us if you're suffering from laryngitis. Or if you're feeling proactive, you can take care of things yourself with a free account at the signup page if you need to get started at ludicrous speed.
So go ahead, do your research, and put us to the test. We may not look like much, but we make the Kessel run in less than 12 parsecs, and that was worth something in a more civilized age a long time ago.