Data Enrichment & Validation

How to CASS Certify Mailing Lists Cost-Effectively

September 22, 2020
Inkit Team

Regardless of multiple budding third-party providers, the United States Postal Service remains the main monitoring agency when it comes to address verification. Through CASS mail certification, it sets the rules for data standardization and formatting. If someone doesn’t meet CASS verification, they cannot qualify for USPS mailing discounts and, most importantly, lose their reputation in the eyes of end-users because of address data accuracy issues.

To help you better understand what is CASS mail certification, what type of businesses and industries need it, and how much CASS mailing address verification may cost, we’ve prepared a concise guide article. Keep reading to find out:

  • What is CASS mail certification and what place does it take in the mailing list verification process?
  • Who needs CASS mailing address verification (software vendors, businesses, and mail recipients)
  • How to CASS certify a mailing list without overspending

What Is CASS Mail Certification? CASS Mail Certification for Mailing List Verification Process

The Coding Accuracy Support System (CASS) is the certification system created by USPS for validating addresses. It was established to ensure the accuracy of data generated by tools that process, correct, format, and match mailing addresses. CASS mail certification is provided to mailers and software vendors that have managed to prove the quality of their address-verification services by following the USPS standards.

Generally, to become CASS compliant, software vendors have to meet only two requirements. They need to use DPV (delivery point validation) and LACS (Locatable Address Conversion System):

  • Delivery point validation (DVP) is a checkup performed to make sure that USPS will deliver the mail to a specific address. The main goal of this procedure is to ensure that the postal address is real and active.
  • The Locatable Address Conversion System (LACS) is a database supported by 911 emergency services. It records changes to addresses to speed up location searches in case of emergency.
address validation

Once the product gets the CASS mail certification, USPS lists it on its website and documentation. This indicates that the software can successfully detect valid and mailable addresses as well as increase the accuracy of ZIP+4 code, carrier route, and five-digit coding. Note that the CASS mail certification must be renewed annually.

Why is CASS mailing address validation so important for postal address verification?

CASS mailing address validation is a mandatory stage of the regular data verification procedure. Without a proper standardization and data enrichment offered by CASS compliant tools, the quality of address information deteriorates, and the final data matching becomes much less effective. As a result, mailers will have more difficulties reaching the target at the first attempt. This, in its turn, increases return rates, harms your ROI, and thus, results in financial losses.

Benefits of CASS Mailing Address Verification for Software Vendors, Businesses, and Mail Recipients

There are several key categories of stakeholders that can benefit from CASS mail certification. They range from the owners of CASS certified software to average US mail recipients who always feel the advantages of enhanced mailing services. Let’s talk about these groups in more detail.

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Software vendors and CASS mailing address verification

Anyone working on standardizing address, address updating, or validation tools should tap into the advantages of CASS mail certification. First of all, the acknowledgment and support of the United States Postal Service will bring you more customers. CASS verification is another seal of excellence for your product that shows that you care about regulatory compliance and data accuracy. Secondly, you will be able to access USPS databases with move updates and other crucial information. USPS is the most reliable source of the latest address data. Besides, USPS provides automated postage rates for mailings processed through the CASS-certified software. Hence, by gaining the CASS certification, you will also make your CASS verification software more cost-effective.

Business owners and CASS mailing address verification

On the one hand, businesses regularly deal with customers that change their place of residence and need their correct addresses to stay in touch. The use of accurate CASS-certified software allows them to obtain updated address data to deliver the necessary communications in time and support quality customer relationships. On the other hand, companies also often move from one place to another. If their information is not updated through data verification tools, they might stop receiving critical documents and updates. This disrupts business processes and may lead to miscommunication.


Another reason for businesses to leverage CASS mailing address verification is the USPS postage discount for barcoded mail. CASS-certified software is one of the primary requirements for becoming eligible for additional mailing perks. USPS requires senders to check their mailing lists against the master list of USPS postal addresses. After the mailing records are validated, businesses can add barcodes to their mail enabling the Post Office to automatically sort mail pieces. Since the sorting process is optimized, USPS charges less for delivery. This makes direct mail cheaper and boosts ROI (For more details on how direct mail validation boosts ROI, visit this page).

Recipients of mail pieces and CASS mailing address verification

Improved mailing services turn direct mail into a highly reliable channel of communication. Mail recipients enjoy accurate mailing and receive better customer service both from the postal office and third-party companies. Although they don’t pay for CASS verification software, they indirectly benefit from it.

How to CASS Certify a Mailing List Without Overspending

CASS verification with conventional approaches

If you are a small or medium-sized mailer, there’s usually no point in CASS certifying your mailing lists on-premises with specialized matching software. Such tools may cost $800 per year or more. Given that CASS mailing address verification software is just one of multiple services needed, you risk squandering your budget.

That’s why certification through third-party companies is a preferred option for most SMEs. You can validate a separate list by paying several dozens of dollars and start using it within a few hours. If you have one contact list that isn’t updated too often, such an approach is an effective way to enjoy the most recent mailing data while staying cost-effective.

Those who use the National Change of Address (NCOA) service, can benefit from CASS certification as one of the add-ons offered at no extra charge.

CASS verification with automation tools

Some direct mail automation services, including Inkit, have built-in CASS verification capabilities. This means that when you subscribe to them, you get address updating, standardization, and validation in the package. You don’t need to worry about finding a separate service to CASS verify your mailing lists. Apart from this, Inkit provides a range of other benefits for mailers:

mail tracking
  • Inkit doesn’t only validate customer information to verify the deliverability of addresses, it enriches customer data with additional details. You can even find out postal addresses based on emails.
  • Inkit is not positioned solely as a CASS verification tool, it does much more. Inkit fully automates mail printing, delivery, and tracking. Therefore, you can cover all mail fulfillment stages, from address verification to shipment, with a single product.
  • Inkit offers the most favorable mailing rates possible, so there is no need to struggle for USPS barcode or bulk discounts. You can send one postcard and a batch of custom invoice letters with equal ease in real-time.
  • Inkit smoothly integrates with third-party solutions, which makes it a great asset for software developers who need to build mailing functionality into their products.

Have any other questions about Inkit’s CASS verification сapabilities? Submit a request and we’ll get in touch shortly.

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