Address Verification

Pinar Tuncel
Pinar Tuncel
  • Updated

Postal Address Verification (also known as Address Standardization, Address Validation, Address Verification, and CASS Certification) is the process used to check the validity and deliverability of a physical mailing address. For domestic address errors, it is one of the best failsafe's against undelivered packages. According to the United States Postal Service, an address is valid (or mailable) if it is CASS-certified, meaning that it exists within the comprehensive list of mailable addresses in its system.

Whiplash incorporates our Shipping Label Providers' address verification in-app and it is used for all US Domestic mailings.

It is important to note that we will flag an address as invalid, but are unable to provide auto-correction to any address that has:

  • Multiple errors in the address (e.g. invalid ZIP and street name in the same address)

  • Multiple address possibilities (e.g. a bad address can be interpreted to be two different verified addresses)

In short, our address verification tool will correct to a reasonable extent, but it is much safer if we flag these problematic addresses instead of assuming. The last thing we want to do is suggest the wrong address based on vague errors.

While address correction works properly most of the time, addresses will not always be changed and incorrect addresses coming in from your integration may still ship incorrectly. The carriers make every attempt to complete delivery. However, Whiplash is not responsible for incorrect addresses coming directly from the integration or through carrier changes.


What are the signs of a "good" address?

The system and label provider are looking for things such as this upon verification:

  • Streets, Roads, Drives, Avenue, and State should be abbreviated
  • Apartments and Suite Numbers should be entered on address line one in most cases, with proper abbreviations (Use this for an apartment: Apt. 3 or #3 – Or this for a Suite: Ste. 3 or #3)
  • A verified address in conjunction with a phone number is also required for the purpose of creating a return label on our platform. If you do not include a phone number, you will be unable to create a return label from the original order.

Non-English Language Characters

Certain Non-English language characters are not recognized by the label provider and must be removed. Examples of this would be quotation marks, asterisks, foreign language/text, etc.


Address Verification Statuses


The address has been verified to be an exact match with the EasyPost Address Verification tool. 

Verification Skipped

Address Verification was not run on the address provided. 

Not Verified

Our label providers' address verification tool was unable to find a match close enough to make corrections. 


Using Notification for Alerts Regarding Order Issues

 Note: Setting up notifications for alerts is highly recommended. 

Rules can be set to notify you in the event that an Address Verification was skipped or was not verified, however, it does not prevent a package from shipping to the address provided for Whiplash to ship to. Please contact for assistance setting up a notification rule on your account if you would like to review addresses that were not verifiable.


Shippo's Address Verification Tool

The simplest and most automated way to validate an address at checkout is through an API. For instance, you can use Shippo to validate your address. Shippo taps directly into USPS’ address database to verify all addresses so that you will not end up with a non-deliverable shipping label.

Shippo’s address validation API only corrects addresses if they are positive that it does not actually change the intended address. Whenever the address validation is ambiguous, the address validation service returns the original address (or an error) and usually includes a message such as “ZIP and city are a match, but the street address is invalid”.


Quick Tips for Address Verification


Related Questions:

What is Address Verification?

Why was an address not automatically corrected?

What is considered a valid address?

What are the address verification status'?

How do I set up notifications to be alerted about order issues?

How does Shippo's Address Verification tool work?