Register Log in Shopping cart (0)

All About The USPS API

The USPS API is a zip code API provided by the United States Postal Service to provide developers of web-based applications access to the complete USPS database of postal address information for the United States.

(You can access a ready to use version of the USPS Zip Code api data for free.)

In reality, the USPS offers multiple APIs. They are as follows:

  • ZIPCode API
  • Address Verification API
  • Address Standardization API

Each of these APIs perform specific functions such as zip code, zip+4 appending, address validation, address normalization, and more.


USPS Address Verification API

If you're just looking to use the USPS API itself, here is a list of resources:

USPS Web Tools:

NOTE: A faster and easier way to access the same data of the USPS database is to use the Zipcodedownload Zip Code API service instead.

The Zipcodedownload API:

  • contains all of the data of the USPS database
  • Also contains Canada Postal Code data
  • is fully documented
  • has great support
  • is super easy to integrate
  • has 100% uptime

Customer Approved

Awesome services and products! I stumbled across your website through a Google search for ZIP Code API. It's a great tool and very affordable. - Jacob Harris


Why is the USPS API status relevant? Because even though the US Postal service owns the data and manages all of the addresses, zip codes, etc. in the USA, their API is known for its lack of consistent uptime. This can certainly be a big problem for most companies.

The USPS API might be free, but it comes at a huge price: reliability.

Besides having poor documentation and less than stellar support, the USPS APIs are known among developers for having issues. No one needs to deal with that.

So, if the USPS API system isn't reliable, what's a developer to do?

Simple: Zipcodedownload. We built the first USPS zip code API and have been the leader in the industry ever since.

The Zipcodedownload Multi-Function ZIP Code API is a RESTful service with JSON and XML response data types. The Zip Code API is Perfect for:

  • Covers U.S. Zip Codes and Canadian Postal Codes
  • Address form autocompletion and validation
  • Distance, Radius, location and more
  • Find Zip Codes
  • RESTful Service with JSON/XML Response
  • Accurate licensed data, updated monthly

We invite you to visit our Zip Code API page to learn more about how Zipcodedownload can be your Zip Code API provider: Learn More about ZIP Code API