A web search for "address verification" will lead you to two different topics that are related but significantly distinct. They are almost identical in name. The results are Address Verification System (AVS) and POSTAL address verification.

What Is Address Verification?

The Address Verification System (AVS) is a method that credit card processing systems use to verify that the account on the credit card matches the billing address on file. You'll find another good article about credit card Address Verification System (AVS) here.

Address verification (also called address validation) is a very broad term that covers any means used to check to see that an address is valid. According to the US Postal Service, an address is valid if it exists within their comprehensive list of deliverable addresses. An address can still be valid (but not deliverable by the USPS) if it is a remote location and only serviced by private carrier such as UPS or Fedex.

Standardize Addresses

Address verification takes an address that can as incomplete as a street and a ZIP code and standardizes it into an address with a street, city, state, and ZIP using universal abbreviations where possible. At this point, you have addresses that can be compared to find and remove duplicates from your system. Even if you are not mailing anything, address verification (standardization) can be used to help you locate all of the duplicate addresses within your own database. If you have a large database, it can be VERY time consuming to try to look through all the address to remove the duplicates. If you can standardize them, you then need only sort by the addresses and all the duplicates will be next to each other making it easy to clean up. Anyone with a database of addresses can benefit from this feature.

Confirm Deliverability

Once you have a standardized address, the address verification process continues. The address is then compared against the entire list of deliverable addresses in the country to determine if it is a valid (deliverable) address. If it deliverable, it will be assigned a ZIP+4 number something like this: 12344-5678, where the first five digits are the ZIP code and the trailing four digits are the delivery point. An address with a ZIP+4 code (or nine-digit ZIP code) is considered to be deliverable and thus it is validated.

Find Out WHY An Address Is Bad

There are a number of reasons why an address would fail to be validated and the process of address verification will help you to know the reasons. It is usually more complicated than just finding out that the address doesn't exist. Many times the street, city, state, and ZIP are all correct but the house number is wrong. If you were to mail a letter to an address like this, it would come back to you. But, if you can know that it will return BEFORE you mail it, you can do some more detective work to find the correct house number and then successfully mail the letter.

As you can see, address verification is not just for mailing and certainly not just for large companies. There are many more uses for address verification, not just the ones mentioned here. It doesn't require a large commitment of time or money. In fact, some address verification services don't even have a minimum. You can verify just one address or ten million addresses.

Address Verification Providers

US Postal Service - One at a time address verification.

QAS - Address verification and other data services.

Satori Software - Address verification and other data services.

SmartyStreets - Address verification for single addresses, batches, and a live address verification API.