DOTS Address Validation - US 3
Fast and Accurate USPS®
Certified Address Verification
Real-time CASS Certified™ Address Validation
Instantly verify, correct and append US addresses
Near-perfect match accuracy with updates mirroring the USPS

Our USPS CASS Certified address validation service matches and corrects mailing addresses using the latest USPS and proprietary data sets available, ensuring your mailing records are always accurate and up-to-date. The service helps improve internal mail processes and ensures cost-saving delivery rates by verifying and standardizing addresses, while flagging for vacancy, returned mail, and general delivery addresses. With the API’s sub-second response times, the service can be used in real-time to help customers and leads correct errors at the time of entry, increasing customer satisfaction and reducing customer service inquiries.

Our industry-leading, GetBestMatches operation combines Delivery Point Validation (DPV) to verify an address is deliverable, Residential Delivery Indicator (RDI) to identify residential or business, and SuiteLink (SLK) to add secondary suite information for businesses, into one robust API call to our USPS CASS Certified database engine.

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How US Address Validation Works
Please select an example address to see how our service corrects and appends US mailing addresses.


Choose from common use cases

Postal Code

Request URL

Real-Time API Responses

See below for the full response from our US Address Validation service.

Service Response


Please select input data to see results

Address127 E Cota St
CitySanta Barbara
Is Residentialfalse
DPV DescThe input record is a valid mailing address, but is missing the apartment or rural route box number
DPV Notes11,22,26,39
DPV Notes DescDefault ZIP+4 record used to certify the address,
Address exists but mail is being returned,
The input address matched the ZIP+4 record,
Highrise apartment/office building address
Corrections DescZIP code change
Barcode Digits931017603992
Carrier RouteC006
Congress Code24
County Code083
County NameSanta Barbara
Fragment House27
Fragment Pre DirE
Fragment StreetCota
Fragment SuffixSt
Fragment Post Dir
Fragment Unit
FragmentPMB Prefix
FragmentPMB Number
View Full results


For Developers

Our services are built API-first with a focus on data quality and ease of integration.
We support REST, SOAP, GET and POST requests over HTTP/S outputting in XML and JSON formats.

Our API web services are compatible with all major programming languages and we have over 200 pieces of sample code (both snippets and full solutions) available to help with your integration.

Features and Benefits




Uptime Guarantee


Support Engineers

  • Proprietary database of over 165 million unique addresses is continuously updated
  • CASS™-certified software standardizes, and validates addresses, correcting typos and missing postal information including bad street names, cities, states, and ZIP codes
  • Regularly updated database of USPS® street addresses
  • Returns DPV data for all supported operations
  • SuiteLink (SLK) data appends secondary suite information to business addresses
  • Appends ZIP+4 codes
  • Delivery Point Validation (DPV) verifies that the address is deliverable, and flags for vacancies and addresses that are returning mail
  • Residential Delivery Indicator (RDI) identifies addresses as residence or business
  • Appends addresses with carrier route and barcode digits for easy sorting and delivery
  • USPS® address verification API helps improve the efficiency of mailings, reducing costs associated with lost, undeliverable, and returned mail
  • Improves customer satisfaction by helping ensure customers receive their orders, marketing materials, sensitive correspondence, and special offers quickly and without unnecessary delays
  • Runs in real time, allowing for instant verification at the point of entry
  • API instantly corrects and appends address information
  • Standardizes addresses to meet USPS® standards, allowing for improved deliveries -- and potentially lower bulk mailing rates
  • Flags residential addresses to identify potential additional shipping charges and flags areas with general delivery services
  • Runs on demand to ensure mailing lists are as accurate as possible despite changes of address
  • Response time as fast as 150 milliseconds
Additional Resources
Three Ways to Use US Address Validation
Real-Time API
Cloud Connectors
Connects with major marketing, sales and
ecommerce platforms
List Processing
Securely upload lists
for processing

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