What is address verification/validation?

Address verification and address validation are interchangeable terms for the process of checking an address against an authoritative address database, whether that database focuses on a single country, a region, or addresses worldwide. 

When an address matches a known address in the database, it’s considered valid. When no match can be made, it’s considered invalid.

An address verification or validation application programming interface (API) is a mechanism that completes the matching process, then communicates its findings to another software component. 

For example, when you’re shopping online and complete an order form, your address may be sent to an address validation API for verification. The API verifies the address, and the form will use the information it returns to let you know whether it’s deliverable if you entered it correctly, or that you need to make changes if it failed to validate. It all happens in real time.

Beyond ecommerce, address verification APIs can be used by businesses in: 

• P&C insurance to match and deduplicate records across teams and systems
• Healthcare to improve patient matching and minimize HIPAA violations
• Telecom to improve service installation success and manage telecom infrastructure
• Finance to prevent fraud and comply with KYC and AML regulations
• Real estate to accurately list properties and flag potential scams
• Last-mile delivery to navigate to the right delivery location on the first try
• Government to deduplicate voter, taxpayer, and property records and reduce returned mail
• Education to correctly assign school districts and pass audits

To see how address verification works and what it could do for your business, try Smarty’s address validation APIs and validate US and international addresses one at a time or in bulk.

In this article, we’ll cover:

How address verification works

1. Parsing
2. Standardization
3. Verification
4. Enrichment

Now it’s your turn

How address verification works

Address verification is a little more complicated than checking addresses against an authoritative database. Before addresses can be verified, they typically need to be parsed and standardized. After verification, addresses are often enriched with metadata. 

Here’s how address verification typically works, in four steps.

1. Parsing

Address parsing is the first step of address verification. When you parse an address, you separate it into individual components, such as city, state, and ZIP Code. For example, the address 40 Oceana Dr W Apt 8D, Brooklyn, NY 11235-6669 can be broken down into the following components: 

• Primary number: 40
• Street name: Oceana
• Street suffix: Dr
• Street direction: W
• Secondary designator: Apt
• Secondary number: 8D
• City name: Brooklyn
• State abbreviation: NY
• ZIP Code: 11235
• ZIP+4 Code: 6669

2. Standardization

After an address is parsed, it’s ready for address standardization, which formats an address to match the local postal authority’s standards. Address standardization also corrects misspelled components, fills in missing components, and abbreviates spelled-out components (e.g., shortening “Street” or “St” or “Maryland” to “MD”). That way, the addresses can match with registered addresses in the local postal authority’s database during verification.

Here’s an example: 

Address standardization also helps businesses across industries identify and flag duplicate records. Even though they point to the same underlying location, the two addresses above may look different because of variations in abbreviations, formatting, and secondary information. Standardizing those addresses makes potential duplicates easier to spot and resolve.

That can help teams:

• Investigate potential fraud: Customers may intentionally or unintentionally use variations of the same address to appear as separate people, households, or accounts. By identifying records tied to the same standardized address, teams can flag suspicious activity, such as repeated claims for promotional offers, incentives, reimbursements, or insurance benefits.
• Deduplicate customer and operational databases: Duplicate records can inflate customer counts and distort your understanding of the people and locations you actually serve. Resolving duplicates gives teams a clearer picture of customers, households, properties, and accounts.
• Improve customer and market analysis: Cleaner records make it easier to accurately assess customer distribution, geographic coverage, market penetration, and opportunities for expansion without duplicate entries skewing the results.
• Reduce redundant work and costs: Duplicate records can lead to multiple mailings, repeated outreach, unnecessary data processing, and conflicting updates across systems. Identifying them helps teams consolidate records and maintain a cleaner source of truth.

3. Verification

Once an address is properly formatted, it can be verified. The address verification API matches the address against an address verification provider’s database. If there’s a match, the address is valid. If not, it's an invalid address, which comes in several types:

• Incorrect address: Addresses that include so many incorrect components, formatted errors, or misspellings that they can’t be accurately corrected.
• Imaginary address: Addresses that don’t currently exist, but could in the future or have existed in the past (e.g., addresses that have recently been condemned, demolished, or are otherwise no longer in use).
• Address not occupied: Addresses marked vacant by the USPS that no longer receive mail.
• Address not registered: Addresses that haven’t been registered with the local postal authority, such as new builds.

Address verification providers validate US addresses against the official USPS address database, which includes more than 170 million addresses serviced by the USPS. However, there are over 20 million valid addresses outside the USPS’s delivery network that aren’t included in their database. These locations are called non-USPS addresses. 

Non-USPS addresses are often found in rural areas, in regions with severe weather conditions that are too harsh for mail carriers, or in new developments. While the USPS doesn’t deliver to these locations, other private mail carriers often do. 

That’s why address verification providers like Smarty verify addresses against their own databases, which combine the USPS database with addresses from several authoritative private and public sources.

Beyond the US, most countries have their own respective address formatting and databases. To learn more about international address verification, check out our ultimate guide to global address formatting!

4. Enrichment

Address enrichment is the process of appending additional data to a verified address. What that additional data includes varies by provider and can range from persistent, unique identifiers to latitude and longitude coordinates.

For example, Smarty’s address verification API enriches addresses after verification and returns them with up to 55 points of address metadata, which includes Residential Delivery Indicator, vacancy status, county FIPS code, latitude, and longitude. (Check out the full breakdown of each datapoint here!)

Now it’s your turn

And that’s a wrap! After enrichment, the API returns a clean, verified address (or no match) along with the data your workflow needs—whether you use verified addresses for claims processing, patient matching, delivery route optimization, or another process entirely. 

Now that you know how address verification works, go ahead and verify a single address or an entire list of addresses! Still have questions? Talk to an address data expert!