Why Won't My Address Verify / Validate? - Smarty (2023)

Why Won't My Address Verify / Validate? - Smarty (1)

USPS Doesn't Recognize My Address!

For an address to be valid, it must match a corresponding address in the official USPS address databasewhich can be accessed through the USPS APIs. If anaddress contains any incorrect data, it will not match a corresponding address in that database, and istherefore "invalid". Sometimes, an address will not validate because the address is marked as "vacant" by theUSPS. Additionally, a new address, an unregistered address, or one located within a postal code primarilyserviced by PO boxes, would all fail to validate. The best way to be sure an address is valid is to verify the address before you mail or ship something.

Table of Contents:

  • How to Perform Address Validation
  • Bad Addresses
  • How Do I Get the USPS to Recognize My Address
  • "But UPS Delivered There; That Means It's Valid,Right?"
  • What Do I Do When an Address is Invalid?
  • Conclusion

How to Perform Address Validation: A Detailed Guide

Some addresses won't verify because, for one cause or another, they're invalid.

It's a painful truth, and it happens to the best of us. You think you're being smart. You think you're takingall the right steps, and validating your addresses before you try to ship something. And then, the unthinkablehappens: Your address is invalid.

But there are logical explanations for events like these, and we can all find peace by seeking to understand the"why" of our situation. In other words, if you want to know what to do or how to fix it, you have to know whatbroke first. And before you can do that, you need to know what it's supposed to look like when it doeswork.

Address Validation

Address validation (often called address verification) is the process of checking to see if an addressis real. And it's a simple process; explaining it is as easy as 1-2-3:

  1. Address Standardization and Parsing
  2. Checking the Database
  3. Returning a Value

Let's look at how to use the Smarty (formerly SmartyStreets) address verification APIto perform these steps.

Step 1: Address Standardization and Parsing

First, a submitted address is standardized. This means that anyincorrect formatting is rectified. House number, street name, city, etc. are all organized, spelled, andabbreviated correctly, according to the official standards of the postal system that the address belongs to.In the US, for instance, "Street" is changed to "St.", "Utah" is changed to "UT," house numbers are listedbeforestreet names, and so forth. This is done so that the address can be properly matched againstUSPS address validation.

During this step, other minor errors are also corrected. Misspelled street or city names are fixed, and missinginformation is filled in. This can only go so far, however—there's little that standardizing can do if thegiven address lists the wrong street name, or if the street name is missing. City names are possible ifthe postal code and street address are correct. Likewise, a missingor incorrect street designation can be fixed, as long as there's not more than one street with that name in thecity.

Here's an example of a correct address:

2116 Beresford Rd., Smallville, KS 67524 

Now suppose that the aforementioned address had been submitted with some incorrect information or an incorrectformat. Standardizing can fix things like an incorrect street designation, misspelled city, or missing ZIP Code, provided it has enough other information for context:

2116 Beresford St., Smllvile, KS

(Wrong street designation, misspelled city)

It can't fix things like an incorrect street address or city name, or an incorrect city or state name if thepostal code is missing:

2115 Hartford Rd., Smallville, KS 67524

(Incorrect address number, incorrect street name)

In short, if it can identify what it should be, then it can make the correction, but without the proper context clues the address is just wrong. Which leads us to the other half of step 1: parsing. Address parsing in general is an effort to disassemble a line of data, identify its distinct parts, and label them. This is a technique frequently applied to address validation, as it helps make both the standardizing and validating steps more effective.

Properly identifying the moving parts of an address can make it possible to fill in or correct more data thatwould normally be possible with standardization alone. This means there's a better chance of your addressvalidating, even if you wrote some of it down wrong.

Like standardizing however, parsing is not foolproof; parsing often runs into little hiccups, like when tryingto differentiate between

123 Bedford St., Martin, Colorado 


123 Bedford, St. Martin, Colorado 

where the first address lists "Bedford Street", and the second lists "Saint Martin city", withthe problem words abbreviating to an identical "St."

Parsing is usually done in conjunction with standardizing, though a few validation providers do it as a finalstep after validation.

Step 2: Checking the Database

Once address cleansing has been performed and properly labeled viastandardizationand parsing, it's then taken and compared against a relevant database. The database used is the one that's theauthoritative standard for whichever postal system you're using. Usually that database is the one kept by thepostalorganization run by that nation's government, like the USPS in the United States. A search is made to see if theaddress in question is on the official list, and if it is, it "validates", and is marked as a real, activeaddress.

Failure to validate is the focus of this article, but the many different "whys" deserve their ownexplanations, so we'll circle back to it in a little bit. The short answer is that any address not listed in thedatabase doesn't exist as far as the postal system is concerned, so it's marked "invalid."

In practice, sometimes you aren't validating an address in order to mail a letter or package. Instead, you justneed to know that the address is real. This occurs frequently in the process of merging and managing customerdatabases. Since the USPS only includes addresses that they deliver to and since there are millions of addresseswhere the USPS doesn't offer door delivery, Smarty starts with the USPS address database and thenadds additional public and private sources to give broader coverage. When an address validates that didn'toriginatefrom the USPS database, we will tell you so.

Taking this approach, allows you to validate addresses for shipping purposes but also for database management oranything in between.

Step 3: Returning a Value

Last, the address data is returned to the user, complete with a valid/invalid status. This is accompanied by, ifthe validator provides it, an explanation of why it didn't validate or what part of the address failed tovalidate.

The response a validation provider returns to you may also include any supplemental information that theprovider compiles regarding addresses that are submitted to them. Many providers include things like geocodes that correspond to the address, RDI labels, or time zone information. This supplemental information canrange from nonexistent to exhaustive, depending on the company providing it.

This concludes our tour of the address validation process.

Bad Addresses

Now for the fun part. Addresses go wrong and fail to validate for a number of reasons, so while this is not anexhaustive list, what we've put together here is thorough. The following list should cover just about everyproblem you're likely to experience.

Input Error

Never underestimate the power of humans messing up. Mistakes in the way the data is input, if not screened,often go unnoticed until much later. But even if you're keeping an eye out for them, you're still going to runintoentries that are typed in incorrectly. Severe misspellings, flipping or scrambling numbers in the street addressor the postal code—a little slip of the key like that can cause your address to be invalid.

Incorrect Information

Similar to the above reason, sometimes information is just inaccurate. A wrong street name is put in, or cityname, or postal code. Basically, any inaccuracy too severe for standardization to correct will make the addressinvalid.

Missing Information

Sometimes the problem is not that information is wrong, sometimes the problem is that the information ismissing. It's really hard to validate an address if you don't know the house number or street name. You'll beable to verify the accuracy of the city/state/postal code relationship, but without the actual location of thedestination, you're up a creek.


On occasion, information is fake. People might falsify an address to hide an identity or steal one, or to signup for duplicates of things (among other reasons). Whatever the case, the falsification of information can causean address to come back with an "invalid" result (or worse, you might be accidentally validating someone else'saddress, without knowing it).

Not Serviced

Sometimes the postal service you're validating against doesn't service an area directly. Everything fromPO box–only ZIP Codes in the US to war-torn areas in a third-world country, there are just some places where thepostman doesn't make house calls. If the physical address is not receiving mail, it means that it won't beregistered in the database, and that means any mail addressed to it will be sent back where it came from.

Not Registered

Regardless of which country or what postal service you're dealing with, an address needs to sign up with thatpostal service if it's to receive any mail. It's not the postal system's job to keep track of every availableaddress that exists. It's their job to keep track of which addresses want mail. If you don't speak up,they assume you either don't want it or don't exist (see below). In either case, they won't be giving VIP statusto an address that's not on the list.

New Address

Similar to unregistered addresses, a new address may not yet have had time to sign up for mail, or perhaps themail system is still processing and adding them to the list. The postal service isn't keeping track every time anew house or building springs up out of the ground; that burdens on you. If you occupy a new structure, and youwant to be receiving mail, it's your job to make sure the post office is aware of your presence. Failure to doso will result in an invalid address.


If no one is using the address, there's no one to sign the address up, so it's not on the list.

Does Not Exist

Every now and again, you're looking at an address that doesn't exist. Sometimes it's an address that's recentlybeen condemned, demolished, or otherwise no longer in use. More often, it's because the address never existed inthe first place. No one has a use for an imaginary address. The post office has no use for it, you have no usefor it. So a validation of the address will just tell you that it can't find the address, making it invalid.

How Do I Get the USPS to Recognize My Address

Getting the United States Postal Service to recognize your address doesn't need to be difficult but it may takeafew months to take effect. So, the sooner you get started the better. Addresses managed by the United StatesAddressManagement System (AMS) allows the public to submit address changes. You can find your local AMS officeby entering your city and state or ZIPCode here.

Why Won't My Address Verify / Validate? - Smarty (2)

You will then be provided with the address and phone number of your local AMS office who is in charge of youraddress.They will be able to aid you in getting your address added or corrected with their system.

Why Won't My Address Verify / Validate? - Smarty (3)

"But UPS Delivered There; That Means It's Valid, Right?"

You may be aware that private carriers like UPS, FedEx, and DHL will deliver to locations not recognized asvalid in the authoritative databases maintained by organizations like USPS. If so, you're probably wonderingwhat that means. Do they have their own database, and is it more accurate? Is there something wrong with theauthoritative database? How do the private carriers get away with shipping to these aberrant addresses?

Private carriers market themselves on their willingness to go places that the primary carrier won't. Often,they'll even carry objects and substances that carriers like USPS won't touch. But that doesn't mean they'rebetter, or that the addresses they deliver to are "valid" in the truest sense. Here's a few examples:

  • Physical location delivery for addresses serviced by PO boxes—because private carriers don't have anycontrol over PO boxes, they can't deliver there. Instead, they make home deliveries, bringing the mail orpackage to the physical location as if that had been the mailing address all along. Since it's remote placeswhere this tends to be a problem, and home delivery is required, your shipping costs will likely be higherto accommodate for the extra work they'll have to do.
  • Delivery to locations that don't/can't receive mail—places like warehouses that don't have a place fornormally delivering things like letters and small packages. Under these conditions, it's usually largerobjects that are shipped, and the private carrier is serving a function similar to a cargo shipping company.Because these are special locations, and because larger objects often require larger delivery vehicles andspecial tools for use in delivery, it can cost extra.
  • Addresses not registered/outside the service area—private carriers are also willing to go just aboutanywhere there's someone to receive mail. From the doomsday planner that wants to live off the grid, to theInupik tribe on a remote island in Alaska, private carriers boldly go where no mailman has gone before. Butthat kind of trailblazing means going out of the way and, you guessed it, that makes it cost more.

You might think it's great that a private carrier can go to all these magical and exotic places. But bydefinition, if they're delivering to places that aren't valid, that means you can only ship via privatecarriers (who, you know, cost more).

Now it bears mentioning that courier services like UPS and FedEx sometimes have their own address validationtools, but you should know that at least in their case, not all validation is created equal. These tools don'tvalidate in the truest sense, they just tell you whether they would be willing to take your package to thelocation to see if it's real. And we have to tell you, shipping a package is a terrible way to validatean address.

For example, the UPS validating tool only covers the 50 US states, and it excludes military and diplomatic postoffice destinations. Those are valid addresses that are serviced by the USPS on a regular basis, and UPS can'ttell you that they're real.

Likewise, the FedEx tool lacks some of the accuracy of more reliable validation, like the USPS address validation tools that we provide. For instance, it uses AVS to help fill in missing data, since it doesn't standardize. As for the actual validation, ratherthan comparingthe address against an authorized list, The FedEx system just checks to see if the given address matches a realstate,city, and street, then checks the house number to see if it falls within the available ranges on that street. Ifit does,it "validates" to FedEx standards.

That means FedEx is potentially validating the address to imaginary homes and businesses, and that you might notknow your shipment isn't going to be delivered until you get a box in the mail with a "Return to Sender" stickeron it. They probably don't mind, since they get paid either way, but we're betting that you do.

Here's where the discrepancy comes from, using the US as an example: private carriers are not maintaining aseparate postal system. They are using a system that is already in place—a system established and maintained bytheir competitor, USPS. They're not aggregating and keeping their own database of addresses. All they're doingis delivering things.

This is why we use authoritative databases when we validate. Though private carriers can reach locations thatthe databases say don't exist, they can't be counted on to tell you when an address is real and few, if any,offer internationalvalidation (and we can just imagine the fun of an international package being returned tosender). What is international addressvalidation?

What Do I Do When an Address is Invalid?

For some causes of invalid addresses, there's nothing you can do. For starters, if someone falsified addressinformation, then there is little you can do to track down the correct information. But if the problem was thatsomeone mashed the keys when typing it in, or there was a common mistake in names of places, a human touch canoften resolve what a computer finds impossible. So here are a few ideas on coping with bad addresses.

Double check your data: perhaps there's something you've missed. Maybe a mistake was made atsome point during entry, or something didn't copy properly. It never hurts to give it a second look.

Look for common errors: reversed numbers, commonly misspelled words, checking for accuratestreet designations, you know, the little things. The kinds of things that you might not think much of, but thatthe postmen and women need clarification on, if they're going to get the mail to the right place. As humans,we're creatures of habit, and among our habits are habitual errors. So give the address a look-over, and checkfor the things you get wrong again and again.

Is your address really a PO box?: It may be a real address, but if that house or business ispart of a "post office box only" postal area, you're not going toget a solid validation on it. So check and seeif you're testing an address that won't be registered with the postal system due to the local service structure.

For US addresses, there are a number of tools that can do this for you. In fact, we can do it, andit won't cost you a dime. Just plug in the city, state, and 9 digit ZIP Codeinto ouraddress verification demo and we'll give you a quick breakdown of the ZIPCode, including its"type." If the type is "S" (for "standard") then your address is just invalid. But if the type is "P"(for "PO box"), then you need to know the box number if you ever intend to get mail to those recipients.

Something else you should know: if you do know the PO box number (or think you know it), you canvalidate it, just like you would a physical address. It means the same thing: it's a real address, and it'scurrently being used. Here, we can show you how tosend mail to a PO box

Fill in missing data: Missing data can be a real problem when you're trying to validate, somake sure you've filled in everything you can. The more information you can give, the more accurate thevalidation will be. If you're given an invalid response, double-check and make sure that you've supplied as muchof the address as possible, and give it another go.


"Invalid-ness" is a real problem. If it hasn't affected you yet, it has likely affected someone you know. Everyday addresses are coming up invalid, and if left untreated, packages and letters will bereturned to sender by USPS as an insufficient address or another type oferror. As withmany things, the road to healing begins with prevention: validation can help you identify problem addresses, andthough not every invalid address can be cured, you can find peace of mind in the knowledge of which of youraddresses are real.

So remember, an invalid address has a reason. Those reasons can be the key making a successful effort at addressvalidation, if you know them. And knowing, after all, is half the battle.

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