Unique ZIP Codes

Some organizations (such as large businesses, universities, or government agencies) receive an incredible volume of mail. For efficiency, the USPS may assign organizations like these their own unique ZIP Code consisting of a single delivery point. All mail addressed to a unique ZIP Code is routed internally by the assigned organization rather than by the USPS. If an address includes a valid unique ZIP Code, then the address is always marked deliverable. You can identify addresses with unique ZIP Codes by looking for U1 in dpv_footnotes, or a Q in footnotes.


If you enter the following address (which is obviously not correct), our API will say it is a deliverable address:

Street 1: Vgert45345345345
City:     454545545ab
State:    4A
Zip:      12345

Here are the (abbreviated) results from our service:

    . . .
    "delivery_line_1": "Vgert45345345345",
    "last_line": "Schenectady NY 12345-0001",
    "delivery_point_barcode": "123450001996",
    "components": {
        "street_name": "Vgert45345345345",
        "city_name": "Schenectady",
        "state_abbreviation": "NY",
        "zipcode": "12345",
        "plus4_code": "0001",
        "delivery_point": "99",
        "delivery_point_check_digit": "6"
    . . .
    "analysis": {
        "dpv_match_code": "Y",
        "dpv_footnotes": "AAU1",
        "footnotes": "B#Q#X#"

(Notice the Q# and U1 footnotes.) Why does this happen? 12345 is a unique ZIP Code. Since mail to addresses within a unique ZIP Code is handled by the organization who owns the ZIP Code (and not by the USPS), no verification is performed on the street address. The address is technically deliverable with nothing more than a ZIP Code. The ZIP Code 12345 is kind of in Schenectady, NY and it belongs to the General Electric Co.

How to handle these addresses

Our simplest recommendation is to possibly notify your client that the address belongs to a unique ZIP Code and thus cannot be validated beyond the ZIP Code; precise delivery and correctness is not guaranteed.