LiveAddress API Documentation

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Verify addresses at point of entry

Use LiveAddress API to get instant address verification results on your website, in your app, or in an Office™ program like Excel or Access.


CASS™ Certification

SmartyStreets is CASS-Certified™ by the USPS, and LiveAddress API contains valid and official data within its response. Our certification is renewed annually.

Notification from the USPS regarding CASS™ services: When a mailer uses a CASS-Certified™ software product to validate address information at the point of entry (like our LiveAddress API), he or she can make full use of the ZIP+4/DPV/LACSLink data. When the address is submitted for standardization and delivery point validation, it can be checked using DPV™ to determine the accuracy of the primary and secondary address values. All informational return codes and match footnotes can be interrogated and used to improve address quality.

If the primary address does not DPV confirm (meaning it isn't a deliverable address), the input address can be standardized and a 5-digit ZIP Code can be assigned to the address; however, it may not be updated with the ZIP+4 Code prior to being recorded in the mailer address file.

Any addresses which obtain a ZIP+4 code from an interactive process (such as LiveAddress API) are not eligible for postal automation rates. To qualify for automation rates, these addresses must be subsequently processed using CASS-Certified software which generates the necessary documentation (PS Form 3553) for discounted rates.

Data Updates

SmartyStreets is updated monthly with new address and ZIP Code data provided by the United States Postal Service. These updates meet the USPS requirements for CASS-Certified™ software. Because SmartyStreets is web-based, you do not need to worry about updating any software. These monthly updates include new ZIP+4 data, DPV data, and LACSLink data.

Early Warning System data is updated monthly. This data includes information for new addresses being added to the USPS database.