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USPS Addresses API
What USPS Addresses API is
USPS Addresses API provides address validation and correction for software handling mailing or shipping activity. It standardizes domestic addresses, city and state names, and ZIP Codes to USPS addressing standards, including ZIP+4. Location lookups can return valid cities and states for a ZIP Code, or valid ZIP Codes for a city and state. The USPS API catalog lists REST as the interface style, and USPS APIs use OAuth authentication with a Consumer Key and Secret issued when an app is added in the API Developer Portal. USPS says the enhanced Addresses API adds near real-time updates, improved matching logic, and additional address indicators. Access requires a signed license agreement and tier-based fees from July 12, 2026. Users who missed onboarding must begin license signup through the Business Portal to regain access. Limits vary by API or data type, and terms restrict use mainly to USPS shipping or mailing transactions.
Who it suits
It suits teams integrating USPS address functions into shipping, mailing, or related software. Developers should account for OAuth, licensing, usage limits, and restrictions on address-list creation or resale.
What it does well
- Validates and corrects address information
- Standardizes domestic addresses with ZIP+4
- Looks up cities, states, and ZIP Codes
- REST interface with OAuth authentication
- Enhanced API adds near real-time updates
What to know first
- Paid from $4 with no free plan
- License agreement and tier fees apply
- Terms restrict general use to USPS transactions
- Usage limits may change
Plans
| Plan | Billed and limits | Price |
|---|---|---|
| Tier-based fees | Tier-based fees apply; exact amounts are not stated on the page. · License agreement required · fees apply from July 12, 2026 | On request |
As developers.usps.com lists them, read 9 Oct 2026. The maker's own page has the final word.
Verdict
USPS Addresses API focuses on domestic address accuracy and location lookups for mailing workflows. Its licensing, authentication, usage restrictions, and paid access should be reviewed before integration.
Facts from USPS Addresses API's own pages
- Access requirement
- From July 12, 2026, USPS says use requires a signed license agreement and tier-based fees. · developers.usps.com, 9 Oct 2026
- Address validation
- The Addresses API validates and corrects address information to reduce errors and improve package delivery and pricing. · developers.usps.com, 9 Oct 2026
- API interface
- The USPS API catalog lists REST as its API style. · developers.usps.com, 9 Oct 2026
- Authentication
- USPS APIs use OAuth, and users receive a Consumer Key and Secret when adding an app in the API Developer Portal. · developers.usps.com, 9 Oct 2026
- Enhanced API changes
- USPS says the enhanced Addresses API adds near real-time address updates, improved matching logic, and additional address indicators. · developers.usps.com, 9 Oct 2026
- Headquarters
- Washington, DC · developers.usps.com, 28 Sept 2026
- Intended users
- The API catalog describes its APIs as tools to integrate with users’ own ideas, and the terms describe access for mailing and shipping activity and related software or services. · developers.usps.com, 9 Oct 2026
- Location lookups
- The API can look up valid cities and states from a ZIP Code and valid ZIP Codes from a city and state. · developers.usps.com, 9 Oct 2026
- Maker history
- USPS says its history began in 1775, when the Second Continental Congress appointed Benjamin Franklin postmaster general. · about.usps.com, 9 Oct 2026
- Migration access
- USPS states that users who did not complete onboarding lost access to the Addresses API and must start an Addresses API license signup through the Business Portal to regain access. · developers.usps.com, 9 Oct 2026
- Permitted use
- The general API terms limit use to USPS shipping or mailing transactions unless a specific license allows otherwise. · developers.usps.com, 9 Oct 2026
- Prohibited activity
- The terms prohibit using the service or its data to create address lists or databases for third-party use, and prohibit reselling the service. · developers.usps.com, 9 Oct 2026
- Standardization
- Address Standardization validates and standardizes domestic addresses, city and state names, and ZIP Codes to USPS addressing standards, including ZIP+4. · developers.usps.com, 9 Oct 2026
- Support
- USPS directs users with API issues or quota errors to submit a service request for assistance. · developers.usps.com, 9 Oct 2026
- Usage limits
- USPS says request limits depend on the API or data type and may be changed, and it may restrict use when it suspects data mining or address-list creation. · developers.usps.com, 9 Oct 2026
Where USPS Addresses API stands on Freedom251
- Address Verification Software#27 of 30