Data Enrichment & Validation

Postal Address Verification: Tools & Best Practices

September 8, 2020
Inkit Team

Last year, the United States Postal Service processed around 36 million address changes. What does it mean for someone who uses direct mail for official and marketing communications? If you don’t regularly verify mailing addresses, your chances to reach the wrong recipient or have a letter returned are strikingly high.

There are multiple other reasons why address information may be invalid. The recipient may provide an incorrect street name, choose the wrong format, or share an imaginary mailing address. Yet the actual reason is less critical than the consequences. By sending mail to invalid addresses, a business wastes money and ruins relationships with customers. It often gets late with important information, including bills, invoices, and official notices.

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Fortunately, address verification is one of the challenges that modern software can easily solve. The market offers dozens of tools with versatile functionality to choose from. We will discuss the best of them today. Keep reading to find out:

  • What is postal address verification and how it works?
  • Top tools for postal address verification (the difference between US postal service address verification and third-party multifunctional services)
  • Best practices for US postal service address verification: How to verify mailing addresses best

What Is Postal Address Verification and How It Works?

US postal service address verification is the procedure taken to check the validity and deliverability of a specific mailing address. This process helps the sender to make sure that the mailpiece will reach the destination without any troubles and within the shortest time. As a result, the number of returned mail pieces drops, while the accuracy and reliability of direct mail increase.

US postal service address verification is largely based on two preparatory steps: address parsing and address standardization. During the parsing stage, the postal address is broken down into several constituents, such as ZIP code, state, and city. After that, the parsed address is standardized. In the United States, the standardization process must follow the rules of the Coding Accuracy Support System (CASS), a certification system developed by the USPS. If an address is CASS-certified, this means that its format matches the records in the USPS address database and includes all the necessary details (e.g., ZIP codes or street suffixes). Such a street address can be added to the Address Management System and is considered mailable.

Once the address goes through parsing and formatting, the verification tool looks for the same address in the official address database. That’s when the US postal service address verification happens. If the address matches, it’s valid. If address lookups show no result, the postal address is invalid.

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US Postal Service Address Verification vs Third-Party Tools

Although USPS offers some ways to verify mailing addresses, they have limited capabilities. Third-party alternatives usually include additional handy features that–apart from the postal address verification–can do a lot to make your mailing more reliable and better targeted. Let’s analyze the standard US postal service address verification and the additional features that third-party postal address verification services offer below.

Standard US postal service address verification

First of all, you can check ZIP codes on your address list through the USPS website. Use this page to find a ZIP code by address or view all cities a specific ZIP code covers.

mail letter

Address List Correction Service is another option the United States Postal Service provides. Available through the Address Management System Office, it enables you to submit a printout of your list to verify mailing addresses. For a fee, the service will mark any changes in the mailing addresses.

NCOALink® is a separate product offered by USPS for US postal service address verification. You can use it to compare your current mailing lists with over 160 million change-of-address (COA) records. These records include the names and addresses of businesses, organizations, and individuals who have filed a request to change their addresses. If NCOALink detects that the shared name and address match the old address on its database, it will provide you with new address information where available.

Using a Third-Party Postal Address Verification Tool: The Whys and the Hows

It’s worth noting that third-party tools use some of the USPS capabilities to verify mailing addresses. They follow the postal address verification standards and get the Postal Service license to access official databases, including NCOALink. So you don’t need to worry about meeting USPS requirements when using third-party US postal service address verification tools.

Inkit for postal address verification


As one of the most comprehensive tools on the market, Inkit covers all aspects of direct mail, from address verification to automated delivery and tracking. Therefore, if direct mail is an indispensable part of your marketing or business communications, this tool will meet your needs best. Inkit has built-in delivery point verification functionality that allows you to check the accuracy of contact details, add the necessary values, and format postal addresses based on the generally accepted standards. Apart from this, Inkit fully automates mail printing and delivery. No need to go to the post office and puzzle out mailing rules. Thanks to the rich integration functionality, it can send mailing communications based on real-time triggers remotely. To see how Inkit works and test its features, you can request a demo version by contacting its team.

Three Best Practices for US Postal Service Address Verification: How to Verify Mailing Addresses Best

  • Evaluate the scope of your mailing database before choosing the most suitable option to validate addresses. If you don’t need to verify mailing addresses in batches, you may do with a simple web tool that checks a dozen addresses (or less) per day. In case you regularly run postal address verification, we recommend looking for more advanced services.
  • Give customers a way to update their addresses in your database. For example, you can add a separate web form where customers can share updated information or request them to provide the latest contact details through email.
  • Implement automation services to get accurate addresses easily. There are multiple ways to verify mailing addresses automatically, and Inkit is one of them. Once you connect the tool to your system and database, it will automatically update and verify records.

Want to learn more about postal address verification through Inkit? Contact our team to discuss your needs.

Start verifying addresses today
Don't waste time and money dealing with lost shipments that never made it to your customers.
Start for free