Address Verification

Right place, every time.

With Lob, everything you send arrives at the right place, at the right time—every time. With accurate, immediate address verification, you won't waste another dime sending undeliverable mail. We're CASS-certified, and our seamless, streamlined process gives you time to focus on what really matters for your business.

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Delivery Point Validation

Our API is CASS-certified by USPS for over 169 million domestic addresses to ensure your product gets to its final destination. Our robust data cleansing means less returned mail, lost packages, and operational waste.

Worldwide Coverage

With data from over 240 countries around the world, Lob verifies both domestic and international addresses. No matter where you send mail, we'll make sure it gets there.

Address Standardization

Our intelligent API ensures your addresses adhere to proper postal formatting and autocorrects them when they don't. Got some piece of information wrong? We'll automatically fix it. It's that simple.

How it works

Try out our US verification API or US ZIP Lookup API for free with a few addresses below!


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Everyone gets 300 free lookups per month to start.

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What do these results mean?
Zip Code:
Zip Code Type:

Preferred City

County Fips:
Results will appear here.

Liked the demo?

Everyone gets 300 free verifications per month to start.

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This address is deliverable by the USPS.
The address is deliverable by removing the provided secondary unit designator. This information may be incorrect or unnecessary.
The address is deliverable to the building's default address but is missing a secondary unit designator and/or number. There is a chance the mail will not reach the intended recipient.
The address is not deliverable according to the USPS, but parts of the address are valid (such as the street and ZIP code).
This address is not deliverable. No matching street could be found within the city or ZIP code.


What do these results mean?
Primary Line:
Secondary Line:
Last Line:


Primary Number:
Street Predirection:
Street Name:
Street Suffix:
Street Postdirection:
Secondary Designator:
Secondary Number:
PMB Designator:
PMB Number:
Extra Secondary Information:
ZIP Code:
ZIP Code +4:
ZIP Code Type:
Delivery Point Barcode:
Address Type:
Record Type:
Default Building Address:
County FIPS:
Carrier Route:
Carrier Route Type:

Deliverability Analysis

DPV Confirmation:
DPV Vacant:
DPV Footnotes:
EWS Match:
LACS Indicator:
LACS Return Code:
Suite Return Code:
Results will appear here.

Case Study

How Couchsurfing uses Lob

Couchsurfing connects its members to a global community of travelers, helping them find a place to stay or share their home with travelers. The promise of a cultural exchange and meeting new people may be appealing, but it only works when there is trust in the service. Couchsurfing builds this trust in part via a series of member verifications, one of which entails address verification. This verification program ensures that the address a member provides in their Couchsurfing profile is not only a real address, but also inhabited by that member.

Before discovering Lob, Couchsurfing sent address verification postcards through a traditional direct mail vendor which relied on a manual process: "We were sending these postcards before, but we had to manually compile a CSV file for our vendor every week and the addresses in that file were whatever our members provided, which meant they weren't always accurate or in a recognized format," said Denise Remhof, Couchsurfing Product Manager. "Using the Lob API, we automated all of this—from making sure members were providing deliverable addresses to programmatically sending postcards on-demand instead of through an entirely manual process."

“We're saving time each week that would have been spent managing this program manually. With Lob, we don't even have to think about it anymore.”

After a straightforward integration (Couchsurfing called it "pretty trivial"), they were up and running. "We're saving time each week that would have been spent managing this program manually," remarked Remhof. "With Lob, we don't even have to think about it anymore. That may not sound like a ringing endorsement, but not having to think about it is a big deal."

In addition to time savings, Couchsurfing finds Lob superior to their previous solution in other ways as well. "Lob clearly wins out on all of the dimensions we care about: dynamic postcard updates, price, and speed to delivery," Remhof confirmed. Now that they're sending address verification postcards using the Lob API, the program runs itself and Couchsurfing has more time to work on other things that matter to their business.


API requests per month


manual CSVs compiled

CASS metadata with each US verification

  • Recipient
  • Primary Line
  • Secondary Line
  • Urbanization
  • Last Line
  • Deliverability
  • Primary Number
  • Street Predirection
  • Street Name
  • Street Suffix
  • Street Postdirection
  • Secondary Designator
  • Secondary Number
  • PMB (Private Mailbox) Designator
  • PMB (Private Mailbox) Number
  • Extra Secondary Information
  • City
  • State
  • ZIP Code
  • ZIP+4 Code
  • ZIP Code Type
  • Delivery Point Barcode
  • Residental Delivery Indicator (RDI)
  • Record Type
  • Default Building Address
  • County
  • County FIPS
  • Carrier Route
  • Carrier Route Type
  • Geocoding (Latitude & Longitude)
  • Delivery Point Validation (DPV)
  • DPV Footnotes
  • CMRA
  • Vacant
  • Early Warning System (EWS)
  • LACSLink Indicator
  • LACSLink Return Code
  • SuiteLink Return Code

Smarter mail starts with Lob.

It's dead-simple to get up and running, and our experts are here to help at every step.

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