What Is Postal Address Verification? What an Online Check Can and Can't Tell You

Q: Is postal address verification free?

Checking up to 2,500 addresses per run is free, with no sign-up. Bigger lists run as a paid background job. You pay once, with no subscription.

Published Nov 3, 2026

Postal address verification means making sure an address is right before you send a letter or a parcel. It hides two different questions: is this a real place, and will the mail get there? An online check answers the first one, and you can try it for free.

What is postal address verification?

Checking that an address is real and complete before you send mail to it.For example, 350 5th Ave, New York, NY 10118 is confirmed: it is the Empire State Building.

How do I check my addresses?

Paste or upload them in Address Verification. Every address gets a status. Up to 2,500 addresses are free.

What will you learn in this article?

What an online check can and can't tell you, what each status means, and how to check a whole list step by step.

What Does Postal Address Verification Mean?
What an Online Address Check Can Tell You
What Only the Postal Service Can Confirm
How to Check an Address List, Step by Step
Tips for a Clean Mailing List
Frequently Asked Questions

What Does Postal Address Verification Mean?

Think of wedding invitations, a club newsletter, or parcels from a small online shop. Before you send them, you want to know two things:

Is it a real place? Does the street exist, is the house number on it, and are the city and postal code right?
Will the mail get there? Does the post office deliver to this address, and does someone receive mail there?

The two questions sound alike, but different people answer them.

An envelope with two questions: is it a real place, answered by an online address check, and will the mail get there, answered by the postal service

An online check answers the first question. The postal service answers the second.

What an Online Address Check Can Tell You

An online check compares each address with address and map data. Address Verification on GeoSearch uses open data: OpenStreetMap, OpenAddresses and GeoNames. For every address you get the full, clean address, its coordinates, and a status that says how sure the check is.

Status	What it means	Example
`CONFIRMED`	The address matches a real place.	`350 5th Ave, New York, NY 10118`: the Empire State Building.
`PARTIALLY_CONFIRMED`	Part of the address matches, but not all of it.	`8800 S Wacker Dr, Chicago, IL`: the street is real, but the house number is not found.
`NOT_CONFIRMED`	No reliable match.	`999 Nowhere Imaginary Rd, Zzyzxville`: no such street or town.

Examples checked in Address Verification on November 3, 2026.

When an address is only partly confirmed, a second column says which part is in doubt: the building, the street or the city. In the Chicago example, it is the building: Wacker Drive exists, but number 8800 does not.

The check can only confirm what you give it. Always include the house number, the city, the postal code and, for international lists, the country.

What Only the Postal Service Can Confirm

An online check can't tell you whether mail is delivered to an address, or whether someone lives or works there. That information belongs to the postal service.

Even the post office's own address tools say so. The USPS ZIP Code lookup finds the ZIP Code for an address, but its result "does not confirm that a person or company is at that address".

Businesses that send a lot of mail in the US use address software certified by USPS. The certification is called CASS, and it also tests whether software can match addresses to delivery points. For a few letters or a club list, you don't need it. For bulk mailings, ask your postal service or mailing company.

An online check can tell you	Only the postal service can tell you
Whether the address matches a real place	Whether mail is delivered there
The full, clean address and its coordinates	Whether someone lives or works there
Which part of the address is in doubt	Whether the address can receive parcels

Sources: USPS: Look Up a ZIP Code and USPS PostalPro: CASS.

How to Check an Address List, Step by Step

Four steps: your address list, Address Verification, a status for every row, fix the doubtful addresses

From your list to a status for every address.

Open Address Verification.
Paste your addresses, or upload an XLSX, CSV or text file. From Excel or Google Sheets, save the sheet as XLSX or CSV first.
Choose which columns hold the street, city, postal code and country.
Click Verify. Up to 2,500 addresses are free.
Download the CSV. Your own columns stay, and every row gets its status.
Sort by status and fix the addresses that are not confirmed.

For more than 2,500 addresses, the check runs as a paid background job and you get an email when it's done. The pricing page shows the price. The bulk address verification page explains big lists in more detail.

Tips for a Clean Mailing List

Give every part of the address. House number, street, city, postal code and country. A street name alone can't confirm a house.
One address per row. Keep the street, city and postal code in their own columns if you can.
Add a country column for international lists, or choose a default country.
Fix NOT_CONFIRMED rows first, then look at the PARTIALLY_CONFIRMED ones.
Tidy the format with Address Standardization if your list mixes styles, like "St." and "Street".

Wondering how verification differs from validation? Read Address Validation vs Address Verification.

Frequently Asked Questions

How do I check postal address verification?

Paste your addresses or upload a file in Address Verification, choose the address columns and click Verify. Each address gets a status: CONFIRMED, PARTIALLY_CONFIRMED or NOT_CONFIRMED. Download the CSV and fix the addresses that are not confirmed.

Is postal address verification free?

Checking up to 2,500 addresses per run is free in Address Verification, with no sign-up. Bigger lists run as a paid background job. You pay once, with no subscription.

Does an online check confirm that mail will be delivered?

No. An online check tells you whether an address matches a real place in address and map data. Only the postal service can say whether mail is delivered there. For a delivery check, ask your postal or shipping service.

What is the difference between address validation and verification?

Validation checks that an address is written correctly and has all its parts. Verification checks that it matches a real place. Read more in Address Validation vs Address Verification.

Can I verify addresses outside the US?

Yes. Address Verification works for addresses in many countries. For the best results, add a country column or choose a default country before you start.