Bad address data costs you money before a single mailpiece enters the mailstream. Lob’s Address Verification API catches those problems before they reach production. Here’s how it works and why it matters.
Lob’s Address Verification API checks the validity and deliverability of physical mailing addresses in the US and internationally. For US addresses, it standardizes and corrects address data according to USPS standards. You can use it before mailing to identify undeliverable addresses—or earlier, when customers enter data into your forms, CRMs, and databases. Either way, you can address data problems before they create unnecessary print, postage, or operational costs.
Lob’s Address Verification solution is CASS Cycle O certified by USPS. This means it has been tested against USPS requirements for address matching, standardization, and deliverability.
Each request runs through a multi-step process. Addresses are parsed into components, standardized to postal formatting, and checked against applicable postal data. You can also receive enrichment data such as ZIP+4 codes, county FIPS codes, delivery point barcodes, coordinates, and address type, making your address records more useful as well as more accurate.
USPS defines a standardized address as one that uses the appropriate spelling, abbreviations, formatting, city, state, and ZIP Code information. Without standardization, addresses that look correct to a person may still contain issues such as misspelled street names, missing suffixes, or outdated ZIP Codes. Lob’s API handles this process automatically and returns complete, machine-readable address data.
When you submit an address, Lob’s API breaks it into individual components and returns a detailed deliverability analysis. Possible US deliverability outcomes include:
These results give you more context than a simple valid-or-invalid response, allowing you to decide whether to accept, correct, flag, or reject an address based on your workflow.
Standardization gives you a correctly formatted address. Delivery Point Validation (DPV) goes further by confirming whether that address corresponds to a location that receives mail.
Lob’s API provides DPV analysis using USPS delivery point data. Where standardization might confirm that a street name and ZIP Code are formatted correctly, DPV checks whether the full address—including apartment, suite, or unit information—resolves to an actual delivery point.
The response can also provide details about the location, including whether the address is residential or commercial, vacant, or currently active. It is the final check: Does this specific location receive mail?
The most obvious benefit is avoiding unnecessary spending on mail that cannot reach its destination. But address verification can improve your data and workflows before anything goes to print.
With real-time verification, you can catch and correct address problems when a customer enters information into a form rather than discovering them through returned mail or post-send reports. Lob’s API also uses LACSLink to help update US addresses that have been renamed or renumbered.
Beyond mailing, clean address data can support several operational priorities:
Because Lob’s API is CASS-certified, US address corrections are based on USPS address-matching standards and postal data.
If you are still relying on batch cleanups or post-send reports to find address problems, you are fixing them too late. Verify addresses in real time with Lob’s API and keep bad data out of your pipeline from the start.
Book a demo to see how Lob can help you verify, standardize, and enrich address data before your next send.
Frequently asked questions
FAQs
How can I verify an address?
Use Lob’s Address Verification API to check a US or international address. Submit the address, and the API parses and standardizes it before returning a deliverability result and available address details.
For US addresses, those details may include ZIP+4 information, a delivery point barcode, vacancy information, and address type. You can verify addresses individually in real time or process lists before a mailing goes into production.
What is the difference between address validation and address verification?
The terms are often used interchangeably, but they refer to different parts of the address-quality process.
Address validation checks whether an address is structured and formatted correctly according to postal standards. It can correct spelling, abbreviations, missing information, and formatting issues.
Address verification goes further by checking whether the address corresponds to a real, deliverable location. It can also flag issues such as missing or incorrect unit information and provide a more detailed deliverability result.
Lob’s API handles both processes within the same workflow. Learn more about the difference between address validation and address verification.
Does Lob’s Address Verification API work for international addresses?
Yes. Lob supports address verification for US and international addresses. Submit an international address, and the API returns standardized formatting and available deliverability information based on the postal data for that country.
Coverage and the depth of available address data vary by country, so the specific information returned may differ by destination.
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