Geocodio can return USPS ZIP+4 codes along with some deliverability indicators for US addresses and latitude/longitude coordinates, including PO Boxes.
You can download an example of the results when you add ZIP+4 to a spreadsheet of addresses here or latitude/longitude coordinates here.
If you'd prefer to use an API, you can see our technical documentation here.
The range of ZIP Codes that are associated with this result as represented by the minimum and maximum number.
The ZIP9 code consists of the ZIP5 code, a dash, and the +4 code.
In most cases a single ZIP+4/ZIP 9 code is associated with a location, so the second column is left blank. Some larger businesses may however have multiple ZIP+4 codes assigned to a single address.
If a second address line (i.e. apartment/unit number) is applicable for the given building, it is also required to determine the correct ZIP+4 code.
The type of ZIP+4 result. Possible values are:
A 4-byte code that determines the type of postal route that that servers the address. Possible values are:
A USPS-provided name associated with the address. This is available for businesses that have registered their name with USPS and for most federal and state government buildings including schools and offices.
The building or firm name field takes the secondary address unit into account if available.
If no name is available, the value is blank.
Type of government building (if applicable).
If no name is available, the value is blank.
Facility code associated with the 5-digit ZIP Code
Possible values are:
Indicates whether our not the local post office has a city delivery carrier route.
In some cases an address exists but it is not a valid delivery point for postal purposes. This could for example be because it is an undeveloped lot.
An exact match means that there was no ambiguity with the lookup and that the given ZIP+4 code is the correct and only match for the given address.
Most often, not-exact matches are due to lookups for an apartment or office building that is missing a unit/apartment number.
In these cases it is not possible to determine an accurate ZIP+4 code without supplying secondary address line information.