# USPS APIs and shipping software

The USPS APIs let a business's software verify addresses, price and label packages, and track them.[^1][^2] Developers get access through the USPS Developer Portal and test in a separate environment before production.[^3][^4] Click-N-Ship prints labels with postage on usps.com, and the [Parcel Data Exchange API](https://postalref.com/products/parcel-data-exchange-pdx-api.md) moves manifest files between a shipper's software and USPS.[^5][^6]

Updated November 6, 2026. 59 sources.

## Questions

### How do I create a USPS shipping label at home?

Click-N-Ship, the USPS shipping application on usps.com, lets a customer print shipping labels with postage from their own computer.[^5] The customer signs in to a free USPS.com account to use it, which also offers file upload and bulk edits.[^7] Software built on the USPS APIs makes 4x5 or 4x6 inch [shipping labels](https://postalref.com/guides/package-labels.md), thermal labels included, in file formats such as PDF and ZPL.[^1] Without a printer, a customer can print a label at a Post Office from a USPS Label Broker QR code.[^8]

### How do I use the USPS address validation API?

Software sends a domestic address to the USPS Addresses API, which verifies and standardizes it and adds a missing ZIP + 4.[^2] Like every USPS API, it needs an app on the USPS Developer Portal and an OAuth token.[^3][^9] From August 1, 2026, USPS charges for it monthly, under a license a business requests in the [Business Portal](https://postalref.com/products/business-portal-formerly-customer-onboarding-portal.md) and signs through DocuSign.[^10][^11]

### What replaced the USPS Web Tools API?

USPS retired the Web Tools platform on January 25, 2026, and its users move to the USPS APIs on the USPS Developer Portal.[^12][^13][^14] For tracking, they move to Tracking 3.2, the only Tracking API that [PTR2](https://postalref.com/products/ptr.md), USPS's rebuilt tracking platform, supports.[^15]

### Where do I download Click-N-Ship Business Pro?

Click-N-Ship Business Pro is a label program that users download from the [Business Customer Gateway](https://postalref.com/products/business-customer-gateway.md), USPS's entry point for online business services.[^16][^17] USPS plans to retire it and will advise its users to move to Click-N-Ship.[^18]

### How do I get a USPS API key?

A developer creates an app on the USPS Developer Portal, and the app gives them a key and secret.[^3] The key and secret get an OAuth token, which every USPS API call needs.[^19][^9] The [Business Portal](https://postalref.com/products/business-portal-formerly-customer-onboarding-portal.md), where a business opens its USPS account, can also create and update Developer Portal apps.[^20][^21]

### Does the USPS API have a rate limit?

Yes, each USPS API limits the requests a user may make in a day, by the type of API and data requested.[^22] USPS enforces the hourly call quota on each app, not on each business location or token.[^3] The Customer Access Team at APISUPPORT@usps.gov takes requests to raise it.[^3]

### Is the USPS tracking API free?

From April 2026, the Tracking API and Tracking Webhook are free for merchants and shippers, and for platforms and label providers.[^12] Other businesses pay a monthly fee, charged per tracking number.[^12][^23] Software vendors whose customers send manifests under their own credentials get no free tracking data.[^24]

### Why doesn't the USPS tracking API show origin and destination?

USPS stopped giving package origin and destination details in the Tracking API and Tracking Webhook in June 2025, in every version.[^25] Tracking 3.2, the [PTR2](https://postalref.com/products/ptr.md) version, also differs on purpose from USPS.com in some events and messages.[^15][^25]

## How it fits together

A business that ships with USPS opens a [USPS business account](https://postalref.com/guides/business-accounts.md), which holds three identifiers: a Customer Registration ID, a Mailer ID and an Enterprise Payment Account.[^20] It needs all three to use the USPS APIs, [USPS Ship](https://postalref.com/products/usps-ship.md) and Click-N-Ship.[^20] Its developers then create an app on the USPS Developer Portal and test it in MCAT, the test environment for USPS API users.[^3][^4] USPS Web Tools, the older suite of USPS APIs, retired on January 25, 2026.[^26][^12]

The USPS APIs price a package, create its label and generate its Shipping Services File, the electronic file of manifest and payment information.[^27][^28] The [Tech Sheets for APIs, Click-N-Ship, and USPS Ship](https://postalref.com/products/tech-sheets-for-apis-click-n-ship-and-usps-ship.md) are USPS's documents on these platforms.[^29] A shipper whose own software makes its labels sends its manifests through Parcel Data Exchange or a file-transfer protocol such as SFTP.[^30][^31] USPS Ship, the platform in [paying for packages](https://postalref.com/guides/package-payment.md), prices each package from its manifest and checks it against scans.[^32]

Once USPS scans a package, its tracking platform, [Product Tracking and Reporting](https://postalref.com/products/ptr.md) or PTR, makes the scan events available three ways.[^15] Software asks the Tracking API for a package's latest status, or subscribes to the Tracking Webhook to have events pushed to it.[^12] The third way, Scan Event Extract files sent through Data Transfer Services, belongs to [package tracking](https://postalref.com/guides/package-tracking.md).[^33]

Smaller shippers without a software vendor use Click-N-Ship, which prints labels with postage on usps.com.[^34][^5] Merchants offer their customers return labels through the [Merchant Returns API](https://postalref.com/products/merchant-returns-api.md).[^35] The [Informed Delivery API](https://postalref.com/products/informed-delivery-api-application-programming-interface.md) lets mailers and shippers manage Informed Delivery campaigns from their own applications.[^36]

## The USPS APIs

The USPS APIs are an online platform that lets a business's software request USPS services and data for its shipping.[^37] Each API handles one part of shipping a package, from its address to its delivery.[^1]

| Job | API |
|---|---|
| Verify and standardize an address | Addresses[^2] |
| Price a domestic package | Domestic Prices[^38] |
| Price an international package | International Prices[^38] |
| Create a domestic label and its Shipping Services File | Domestic Labels[^27] |
| Create an international label and its customs forms | International Labels[^27] |
| Link many labels to one form USPS scans at acceptance | SCAN Form[^38] |
| Find a Post Office or destination entry facility | Locations[^2] |
| Get delivery standards or expected delivery dates | Service Standards[^2] |
| Schedule a package pickup | Carrier Pickup[^2] |
| Track a package | Tracking[^2] |
| Register customers by creating customer and mailer IDs | Organizations[^2] |

How a business's software gets access to the USPS APIs.

1. Open a USPS business account in the Business Portal, which issues a Customer Registration ID, Mailer ID and Enterprise Payment Account.[^20]
2. Create an app on the USPS Developer Portal, which gives a key and secret.[^3]
3. Call the OAuth 2.0 API with the key and secret to get a token.[^9]
4. Before making labels, get a payment token that names the payer and the label owner.[^39]
5. Call each API with the token at `apis.usps.com`, the production host.[^9][^40]

Every label needs a payer and a label owner, the Mailer ID that creates its tracking number.[^39][^27] Other roles, such as the platform used to create labels, are optional.[^27] Labels get commercial rates unless the payment call names an authorized account or permit with contract rates.[^27]

A user of the USPS APIs agrees not to make more requests in a day than each API's limit allows.[^22] Each API's limit depends on the API and the data requested.[^22] USPS may change a limit without notice.[^22]

The Addresses API is not free: from August 1, 2026, USPS prices it in tiers, and its use needs a signed license agreement.[^10][^11] USPS charges it monthly, and the month's number of record requests sets one tier for the whole month.[^41][^42][^11] Tier 1 is a flat fee, and tiers 2 to 4 charge per 1,000 requests or part of 1,000.[^11] USPS debits the month's Addresses Usage Fee from the Enterprise Payment Account at the start of the next month.[^11]

As of October 4, 2026, the Addresses API's monthly fees are these.[^42]

| Record requests in a month | Fee |
|---|---|
| Tier 1: up to 2,000 | $10.00 flat[^42] |
| Tier 2: up to 10,000 | $4.50 per 1,000[^42] |
| Tier 3: up to 50,000 | $4.25 per 1,000[^42] |
| Tier 4: over 50,000 | $4.00 per 1,000[^42] |

How a business gets its Addresses API license.

1. Create or log in to a Business Portal account.[^11]
2. Create an Enterprise Payment Account if there is none, prefunded or debited from a bank account.[^11][^43]
3. Accept the updated Terms & Conditions in the Business Portal, at `My Apps > Developer Apps > Manage`.[^11]
4. Add an Addresses API License in the Business Portal, at `My Account > API Licenses`.[^11]
5. Sign the order form and license agreements that USPS sends by DocuSign email.[^11]

USPS Web Tools was the older suite of USPS APIs, for building USPS shipping into websites, call centers and back-office systems.[^26] USPS retired the Web Tools platform on January 25, 2026, and its tracking users move to Tracking 3.2.[^12][^15]

- **USPS Developer Portal**, also called Developer Portal, USPS API Developer Portal: “The Developer Portal provides coding examples and downloadable specifications to accelerate integration.”[^1]
- **Platform**: “The platform used to create labels”[^27]
- **USPS Application Programming Interfaces**, also called USPS APIs, USPS API Platform, USPS suite of APIs: “The USPS suite of APIs enables integrators to standardize an address, price a package, create a label, find a USPS acceptance facility, schedule a carrier pick-up, and track a package from entry to delivery.”[^1]
- **Payer**: “Who is paying the postage”[^27]
- **Label Owner**: “The mailer ID used to create the tracking number and generate manifest files”[^27]
- **Business Portal**, also called COP, Business Portal (Formerly Customer Onboarding Portal), Customer Onboarding Portal, USPS Business Portal: “The United States Postal Service (USPS)Business Portal (COP) offers business customers a modern, streamlined way to create and manage a USPS business account set-up and onboard core services.”[^44]

## Test and production environments

MCAT, Mailer Customer Acceptance Testing, is the environment where USPS Ship and USPS API users test functionality before production.[^4] In MCAT, a developer can try an integration from authentication through label creation.[^45] USPS encourages API users to start in testing, then move to production at `https://developers.usps.com`.[^46]

Credentials belong to one environment: production credentials don't work in MCAT, and MCAT credentials don't work in production.[^4] A token made in MCAT can't call production APIs either.[^9] MCAT's APIs are at `apis-cat.usps.com`, and production's are at `apis.usps.com`.[^19][^40]

MCAT runs every function of the production Labels API, but it watermarks each label and charges no postage.[^39] It holds no operational data such as scans or refunds.[^4] Load tests go to the [Test Environment for Mailers](https://postalref.com/products/test-environment-for-mailers.md) instead, by a service request through Email Us, USPS's web contact page at `https://emailus.usps.com/s/web-tools-inquiry`.[^39][^47]

Parcel Data Exchange, or PDX, the service that carries manifest files, keeps a separate test copy called PDX CAT.[^48] Each PDX upload also names its environment, such as `TEM` for test data.[^49] PDX CAT needs its own accounts and Mailer IDs.[^48]

- **Mailer Customer Acceptance Testing**, also called MCAT: “The objective of the Mailer Customer Acceptance Testing (MCAT) environment is to provide USPS Ship and USPS API users with a capability to validate new and upcoming functionality prior to production.”[^4]
- **Test Environment for Mailers**, also called TEM, Testing Environment for Mailers, TEM (Testing Environment for Mailers): “The Test Environment for mailers (TEM) is a test platform designed to allow mailers to test their ability to submit electronic mailing information such as Full Service (FS) mailings to the Postal Service.”[^50]
- **PDX CAT environment**: “separate from PDX Production and provides an isolated testing environment or “sandbox” for customers to test PDX file uploads, lists and downloads without impacting any Production data”[^48]

## Manifest files through PDX

PDX is a web and API application that carries manifest files to USPS and outbound files back to the customer.[^6] The Domestic Labels API generates the Shipping Services File for each label it makes.[^27] Shippers whose own or off-the-shelf software makes labels send their manifests through PDX or a file-transfer protocol such as SFTP.[^30][^31]

PDX is free for business customers and third-party vendors.[^31] Each call carries a Business Customer Gateway username and password.[^6] PDX skips the Data Transfer Services setup, so a shipper can enroll online and ship the same day.[^31] Its outbound files include the data extracts and error-warning reports that PTR generates.[^31][^51]

PTR2 accepts Shipping Services Files only in versions 1.6, 1.7 and 2.0.[^52]

## Tracking APIs and webhooks

USPS recommends that businesses building tracking into their systems use its Tracking API and webhooks.[^53] The right one depends on the business's need:[^53]

- The Tracking API returns a package's latest tracking details when software asks, by tracking number.[^12] It suits software that wants occasional updates and can't store tracking events.[^53]
- The Tracking Webhook pushes scan events to the subscriber as they happen, for a tracking number or a whole Mailer ID.[^12] USPS recommends it to a business that keeps its own tracking history.[^53]
- Scan Event Extracts are files of scan events, kept for experienced partners that prefer existing transmission methods.[^33]

PTR2, the platform that replaces PTR, supports only Tracking 3.2.[^15] Tracking 3.2 became available on August 15, 2025, and USPS plans to retire Tracking 3.0 in 2026.[^53] USPS also plans to retire the Tracking Summary API, whose data is in Tracking 3.0 and Tracking 3.2.[^3][^25][^54]

The Tracking Webhook offers two subscriptions under Tracking 3.2.[^53] The Tracking Subscription sends the whole event history at each event, with the Tracking API's fields.[^33] The Detailed Scan Subscription sends only the current event, plus extract fields such as Mailer IDs and container information.[^33]

Starting April 2026, USPS controls access to tracking data to improve security and fight fraud.[^12] A label provider or consolidator needs MID authorization for a merchant's Mailer IDs, and other service providers need tracking authorization.[^12] Paid users add a payment token to each Tracking API request or webhook subscription.[^24]

- **Tracking Subscription**: “This subscription provides the tracking results at the time of the event and includes the entire event history, along with the fields available on the Tracking API.”[^33]
- **Detailed Scan Subscription**: “A new subscription that streamlines the payload by delivering only the current event, rather than the entire event history.”[^33]
- **USPS Tracking API**, also called Tracking APIs, PTR Tracking API: “User requests one-time update of the latest detailed tracking information, including package status and delivery updates, for a specific tracking number.”[^12]
- **Tracking Webhook**, also called Webhook, Webhook Subscriptions: “User subscribes to be pushed to scan events as they occur in near-real-time, for a specific tracking number or Mailer ID.”[^12]
- **scan event extract file**, also called CDE, DETEXTRO, Scan Event Extracts (PTR), Scan Event Extract, Customer Data Extract, Customer Daily Extract: “This file contains every scan event that occurs on every package that the mailer included in the Shipping Services file.”[^55]
- **MID authorization**: “provides label providers and consolidators with access to label generation, rates and tracking for select MIDs”[^12]
- **Tracking authorization**: “provides service providers and other companies with access to tracking data for select MIDs”[^12]

## Click-N-Ship and Label Broker

Click-N-Ship is the USPS shipping application on usps.com that prints labels with postage on the customer's own computer.[^5] It serves smaller mailers who use no software vendor and don't presort.[^34] It sends USPS the Shipping Services File, with manifest, tracking and postage payment, for each label.[^34] A business account's `Ship Now` action opens it to print labels.[^56]

Click-N-Ship Business Pro is a label program that users download from the Business Customer Gateway.[^16] Shippers who used it with [eVS](https://postalref.com/products/evs.md), the electronic verification system, had to move to USPS Ship or the USPS APIs by February 2025.[^16] USPS Ship replaces eVS, not Click-N-Ship Business Pro.[^18] USPS Ship brings no change to how Click-N-Ship Business Pro makes and prints labels, and Business Pro users need no other software client.[^18] USPS plans to retire Click-N-Ship Business Pro itself and will advise its users to move to Click-N-Ship.[^18]

USPS Label Broker serves customers without a printer.[^8] It stores a label under a QR code or Label Broker ID, which the customer prints at a Post Office or on USPS.com.[^57][^8] The [Merchant Returns API](https://postalref.com/products/merchant-returns-api.md) can send its return labels to Label Broker.[^8]

- **Click-N-Ship Business Pro**, also called CNSBPro, CNBPro: “In CNSBPro, users can generate labels through the downloadable CNSBPro Graphical User Interface (GUI) from Business Customer Gateway (BCG)”[^16]
- **USPS Label Broker service**, also called USPS Label Broker, Label Broker: “facilitates shipping for consumers without access to a printer. It allows customers to print labels using a QR Code or Label Broker Label ID at a USPS® Post Office® or via USPS.com.”[^8]
- **Click-N-Ship**, also called CNS: “An online USPS shipping application through usps.com that enables customers to print shipping labels with postage from their own computers.”[^5]
- **Business Customer Gateway**, also called BCG, BCG (Business Customer Gateway): “where shippers can manage their mailing activity”[^58]

## What goes wrong

- Credentials and tokens work only in the environment that issued them, so a token from [MCAT](https://postalref.com/products/test-environment-for-mailers.md#mcat) fails in production.[^4][^9]
- USPS may limit or deny [API access](https://postalref.com/products/tech-sheets-for-apis-click-n-ship-and-usps-ship.md) when it suspects data mining, address-list building or requests built to get around its terms.[^22]
- Moving to [PTR2](https://postalref.com/products/ptr.md) changes the data format of the Tracking API and webhooks, so existing users must cut over.[^13]
- [PTR2](https://postalref.com/products/ptr.md) no longer accepts Shipping Services File versions 1.3, 1.4 and 1.5.[^13]
- A [PDX](https://postalref.com/products/parcel-data-exchange-pdx-api.md) account inactive for more than 90 days is deactivated, and five or more uploads a minute may deactivate it.[^6][^49]
- A merchant that generates many unused labels may lose its use of [Label Broker](https://postalref.com/products/merchant-returns-api.md).[^8]
- USPS may revoke [API credentials](https://postalref.com/products/tech-sheets-for-apis-click-n-ship-and-usps-ship.md) for a breach of its terms or for suspected fraud.[^59]

## Index: 24 entries

### Services (10)

- [Addresses API](https://postalref.com/?q=Addresses%20API)
- [Detailed Scan Subscription](https://postalref.com/guides/shipping-apis.md#tracking)
- [Tracking Subscription](https://postalref.com/guides/shipping-apis.md#tracking)
- [Tracking Summary API](https://postalref.com/?q=Tracking%20Summary%20API)
- [Tracking Webhook](https://postalref.com/guides/shipping-apis.md#tracking)
- [USPS Address Validation API](https://postalref.com/?q=USPS%20Address%20Validation%20API)
- [USPS APIs Tracking 3.2](https://postalref.com/?q=USPS%20APIs%20Tracking%203.2)
- [USPS Application Programming Interfaces](https://postalref.com/guides/shipping-apis.md#apis)
- [USPS Label Broker service](https://postalref.com/guides/shipping-apis.md#label-tools)
- [USPS Tracking API](https://postalref.com/guides/shipping-apis.md#tracking)

### Systems (7)

- [Click-N-Ship](https://postalref.com/guides/shipping-apis.md#label-tools)
- [Click-N-Ship Business Pro](https://postalref.com/guides/shipping-apis.md#label-tools)
- [Mailer Customer Acceptance Testing](https://postalref.com/products/test-environment-for-mailers.md#mcat)
- [Parcel Data Exchange](https://postalref.com/products/parcel-data-exchange-pdx-api.md)
- [PDX CAT environment](https://postalref.com/guides/shipping-apis.md#environments)
- [Platform](https://postalref.com/guides/shipping-apis.md#apis)
- [USPS Developer Portal](https://postalref.com/guides/shipping-apis.md#apis)

### Document (1)

- [Tech Sheets for APIs, Click-N-Ship, and USPS Ship](https://postalref.com/products/tech-sheets-for-apis-click-n-ship-and-usps-ship.md)

### Roles (2)

- [Label Owner](https://postalref.com/guides/shipping-apis.md#apis)
- [Payer](https://postalref.com/guides/shipping-apis.md#apis)

### Terms (4)

- [Consumer Key](https://postalref.com/?q=Consumer%20Key)
- [Device Reputation](https://postalref.com/products/tech-sheets-for-apis-click-n-ship-and-usps-ship.md#terms)
- [MID authorization](https://postalref.com/guides/shipping-apis.md#tracking)
- [Tracking authorization](https://postalref.com/guides/shipping-apis.md#tracking)

## Sources

[^1]: [API Tech Sheet](https://postalpro.usps.com/mnt/glusterfs/2024-06/USPS%20APIs%20Tech%20Sheet%20.pdf#page=1), page 1: “The USPS suite of APIs enables integrators to standardize an address, price a package, create a label, find a USPS acceptance facility, schedule a carrier pick-up, and track a package from entry to delivery. … Choose a label size of either 4” X 5” or 4” X 6” including support for thermal labels … Choose from multiple file formats: PDF, TIFF, JPG, SVG, ZPL at 203dpi and 300dpi, or custom label creation … The Developer Portal provides coding examples and downloadable specifications to accelerate integration.”

[^2]: [API Tech Sheet](https://postalpro.usps.com/mnt/glusterfs/2024-06/USPS%20APIs%20Tech%20Sheet%20.pdf#page=4), page 4: “Call Address Standardization endpoint with a single domestic address to verify and standardize street addresses (including city and street abbreviations) and provide missing information such as ZIP Codes and ZIP Codes + 4. … Find the closest USPS Post Office or destination entry facility [e.g., Destination Delivery Unit (DDU), Sectional Center Facility (SCF) or Network Distribution Center (NDC)] by passing in the destination ZIP Code. … Find USPS delivery standards or estimated delivery dates for all package mail classes by entering origin and destination ZIP Code. … Schedule a package pickup at no additional cost (Monday through Saturday, excluding holidays). … Enter your tracking number to obtain near-real-time visibility of shipments as packages move throughout the USPS network from induction to delivery. … Register customers with USPS by creating customer and mailer IDs.”

[^3]: [PTR2 FAQs](https://postalpro.usps.com/mnt/glusterfs/2025-12/PTR2_FAQs_v1.pdf#page=5), PDF page 5: “If you haven’t done so already, you will have to create an app on the developer portal to get access to USPS APIs. … When the app is created, it will give you a key and secret. … The number of API calls per hour is enforced at an application level, not at the CRID or auth token level. … Please reach out the Customer Access Team at APISUPPORT@usps.gov. … USPS plans to retire the Tracking Summary API. … The data from this API is available in the USPS APIs Tracking API v3 and v3r2.”

[^4]: [USPS MCAT - TechSheet](https://postalpro.usps.com/mnt/glusterfs/2026-10/USPS%20MCAT%20TechSheet.pdf#page=1), page 1: “The objective of the Mailer Customer Acceptance Testing (MCAT) environment is to provide USPS Ship and USPS API users with a capability to validate new and upcoming functionality prior to production. … Production/TEM credentials are not supported in MCAT, and MCAT credentials cannot be used in Production/TEM. … Operational data including scans, verifications, disputes and refunds are not supported.”

[^5]: [Publication 32: Glossary of Postal Terms](https://postalpro.usps.com/mnt/glusterfs/2016-04/pub32_glossary.pdf#page=44), page 40: “An online USPS shipping application through usps.com that enables customers to print shipping labels with postage from their own computers.”

[^6]: [Parcel Data Exchange (PDX) API Customer Guide](https://postalpro.usps.com/mnt/glusterfs/2023-09/PDX_API_User_Guide_09142023.pdf#page=6), page 6: “Parcel Data Exchange (PDX) is a web and Application Programming Interface (API) based application that provides the capability for customers to send manifest files to the United States Postal Service® (USPS®) and receive outbound files from USPS, pertaining to domestic and international parcel shipments. … This document is intended for users of PDX who use or plan to use a Representational State Transfer (REST) API based software application to connect to PDX. … All PDX Web Service calls require a USPS® Business Customer Gateway (BCG) username and password. … A PDX account that is inactive for more than 90 days will be automatically deactivated.”

[^7]: [Certified Mail®](https://postalpro.usps.com/mnt/glusterfs/2024-05/Certified%20Mail%20Guidebook_May%202024.pdf#page=10), page 10: “Log in to your USPS.com account and select the Click-N-Ship option. … With a free USPS.com account, you can access additional features available in the new, enhanced Click-N-Ship experience: file upload, bulk edits, and more.”

[^8]: [Domestic Merchant Returns API: User Guide](https://postalpro.usps.com/mnt/glusterfs/2026-07/Merchant%20Returns%20-%20Web%20Service%20and%20API%20Guide%20v2.6%202026-07-20.pdf#page=60), page 60: “The USPS® Label Broker® service facilitates shipping for consumers without access to a printer. … It allows customers to print labels using a QR Code or Label Broker Label ID at a USPS® Post Office® or via USPS.com. … Label Broker label delivery is supported by the USPS® Merchant Return API. … facilitates shipping for consumers without access to a printer. It allows customers to print labels using a QR Code or Label Broker Label ID at a USPS® Post Office® or via USPS.com. … Merchants that generate many unused labels may have their ability to use Label Broker suspended.”

[^9]: [USPS MCAT - TechSheet](https://postalpro.usps.com/mnt/glusterfs/2026-10/USPS%20MCAT%20TechSheet.pdf#page=7), page 7: “An OAuth Token must be generated to call all APIs. … Call the OAuth 2.0 API with grant_type = “client_credentials” and the Consumer Key and Consumer Secret in the client_id and client_secret fields respectively … A token generated in MCAT cannot be used to call APIs in Production or in other environments.”

[^10]: [Addresses API - Tech Sheet](https://postalpro.usps.com/mnt/glusterfs/2026-08/Addressing%20API_USPS%20Tech%20Sheet%20updated%208.13.26.pdf#page=1), page 1: “Effective August 1, 2026, customers can access the Enhanced Addresses API under a consumption-tier pricing model.”

[^11]: [Addresses API - Tech Sheet](https://postalpro.usps.com/mnt/glusterfs/2026-08/Addressing%20API_USPS%20Tech%20Sheet%20updated%208.13.26.pdf#page=2), page 2: “Access to the Addresses API and webhooks requires a signed license agreement. … Start the license request: In the Business Portal, initiate sign-up at My Account > API Licenses > Add an Addresses API License … Sign via DocuSign: After completing the Business Portal steps, you’ll receive a DocuSign email to sign the order form and license agreements … Based on monthly consumption, customer will be charged at a single tier level. … First tier is a flat rate fee. … Tiers 2-4 is charged a per 1,000 transaction fee or fraction thereof. … Charges will appear as an Addresses Usage Fee and will be debited from the Enterprise Payment Account (EPA) … Fees are assessed at the beginning of each month for usage from the prior month … Create or log in to your USPS COP account: If you don’t already have a COP account, create one … Set up an Enterprise Payment Account (EPA): If you don’t already have an EPA, create and fund one using trust or ACH by following these steps … Accept the updated Terms & Conditions: In the Business Portal, go to My Apps > Developer Apps > Manage”

[^12]: [Tracking Access Control Tech Sheet](https://postalpro.usps.com/mnt/glusterfs/2026-03/Tracking%20Access%20Control.pdf#page=1), page 1: “Available on the USPS API platform and available on the WebTools Platform until platform retirement on January 25, 2026. … Starting April 2026, data access controls will be implemented on the Tracking API, Tracking Webhook, and Scan Event Extracts for packages. … Access to the Tracking API and Tracking Webhook will be available at no cost to end merchants, shippers, platforms, and label providers. … Other businesses will be charged a monthly fee for Tracking API/Webhook use. … Tracking APIs: User requests one-time update of the latest detailed tracking information, including package status and delivery updates, for a specific tracking number. … Tracking Webhook: User subscribes to be pushed to scan events as they occur in near-real-time, for a specific tracking number or Mailer ID. … USPS is upgrading tracking data access to enhance security and combat fraud by modernizing and securing customer access. … MID authorization provides label providers and consolidators with access to label generation, rates and tracking for select MIDs. … Tracking authorization provides service providers and other companies with access to tracking data for select MIDs. … User requests one-time update of the latest detailed tracking information, including package status and delivery updates, for a specific tracking number. … User subscribes to be pushed to scan events as they occur in near-real-time, for a specific tracking number or Mailer ID. … provides label providers and consolidators with access to label generation, rates and tracking for select MIDs … provides service providers and other companies with access to tracking data for select MIDs”

[^13]: [PTR2 FAQs](https://postalpro.usps.com/mnt/glusterfs/2025-12/PTR2_FAQs_v1.pdf#page=2), PDF page 2: “If you are not already using the Tracking API via the USPS Developer Portal, you will need to migrate there for any tracking needs. … Please note the data format for APIs and Webhooks will change. … If you are currently using that API, there will be a specification change that will require a cutover. … Shipping Services file versions 1.3, 1.4 and 1.5 will no longer be accepted in PTR2.”

[^14]: [Publication 205 Electronic Verification System (eVS®) Business and Technical Guide](https://postalpro.usps.com/mnt/glusterfs/2024-07/eVS_pub205_July_2024_0.pdf#page=18), page 10: “USPS Labels API – Register online at https://developer.usps.com/apis”

[^15]: [Package Tracking Options and Modernization](https://postalpro.usps.com/mnt/glusterfs/2025-09/Package%20Tracking%20Options%20Tech%20Sheet%20Sept%202025.pdf#page=1), page 1: “The WebTools platform will retire in January 2026, existing users are encouraged to migrate to USPS APIs Tracking 3.2. … The upcoming platform will exclusively support USPS APIs Tracking 3.2, discontinuing support for the legacy Webtools API. … The new platform, PTR2, has been designed from the ground-up to provide improved availability and performance. … The USPS tracking platform, Product Tracking and Reporting (PTR), receives and processes scan events for barcoded packages and makes the data available to customers through 3 delivery methods – Tracking APIs, Webhook subscriptions and file-based Scan Event Extracts. … PTR2 will run in parallel with the current PTR platform until customer migration to the new platform is completed.”

[^16]: [eVS to USPS Ship Migration Tech Sheet](https://postalpro.usps.com/mnt/glusterfs/2025-05/eVS%20to%20USPS%20Ship%20Migration_Tech%20Sheet_05.06.25.pdf#page=1), page 1: “In CNSBPro, users can generate labels through the downloadable CNSBPro Graphical User Interface (GUI) from Business Customer Gateway (BCG), as shown below. … The Postal Service is retiring the electronic verification system (eVS). … This includes customers using Premium Forwarding Services Commercial (PFSC) and Click N Ship BusinessPro (CNBPro). … eVS customers must migrate to USPS Ship or USPS APIs by February 2025. … In CNSBPro, users can generate labels through the downloadable CNSBPro Graphical User Interface (GUI) from Business Customer Gateway (BCG)”

[^17]: [PostalPro: Business Customer Gateway](https://postalpro.usps.com/BCG): “gives you a single entry point for Postal Service online business services”

[^18]: [USPS Ship Frequently Asked Questions](https://postalpro.usps.com/mnt/glusterfs/2026-01/20260106_USPS_Ship_FAQs_0.pdf#page=1), page 1: “There is no change, however there are plans to retire CNSBPro later this year. … Users will be advised to migrate to Click-N-Ship. … No, it is replacing eVS.”

[^19]: [USPS MCAT - TechSheet](https://postalpro.usps.com/mnt/glusterfs/2026-10/USPS%20MCAT%20TechSheet.pdf#page=6), page 6: “These credentials are needed to generate OAuth tokens. … The base URL for all USPS APIs in the Cloud is: apis-cat.usps.com.”

[^20]: [USPS Business Portal (COP) Onboarding User Guide](https://postalpro.usps.com/mnt/glusterfs/2026-03/USPS%20COP%20Onboarding.pdf#page=2), page 2: “The United States Postal Service (USPS) Business Portal (COP) offers business customers a modern, streamlined way to create and manage a USPS business account, set up and onboard core services. … When customers create a USPS business account, they receive a Customer Registration ID (CRID), mailer ID (MID) and enterprise payment account (EPA). … Customers need a CRID, MID, and EPA to access USPS solutions and services, such as USPS APIs, USPS Ship, and Click-N-Ship.”

[^21]: [USPS Business Portal (COP) Onboarding User Guide](https://postalpro.usps.com/mnt/glusterfs/2026-03/USPS%20COP%20Onboarding.pdf#page=34), page 34: “The COP app now includes Developer Portal app creation and update capabilities, allowing users to create or modify their apps directly in COP without needing to switch to the developer portal.”

[^22]: [USPS APIs Terms and Conditions](https://postalpro.usps.com/mnt/glusterfs/2026-03/General_API_Terms_3-30-2026.pdf#page=7), PDF page 7: “The Services have a limit on the number of requests that You may make in a given day. … Such limits are dependent on the type of API used or the type of data requested. … You agree that You will not make more than the limited number of requests per day. … The USPS reserves the right to modify, alter or change these limits without notice for any given API. … You agree that the USPS may limit your API usage or credentials when the USPS has reason to believe that you are datamining or creating address lists or for any other purpose the USPS deems to be warranted. … If USPS determines that errors in Your requests, no-data results, non-conforming requests or the like are an attempt to circumvent restrictions in these terms, the USPS may act unilaterally to deny access to the Services and data.”

[^23]: [Tracking Access Control Tech Sheet](https://postalpro.usps.com/mnt/glusterfs/2026-03/Tracking%20Access%20Control.pdf#page=7), page 7: “Customers who will be subject to a fee for tracking information beginning April 2026, will be charged by tracking number.”

[^24]: [Tracking Access Control Tech Sheet](https://postalpro.usps.com/mnt/glusterfs/2026-03/Tracking%20Access%20Control.pdf#page=2), page 2: “Software vendors who provide label generation or manifest software, where customers of the software are responsible for submission of the manifest and the customer uses their own credentials for integration and upload of manifest with the USPS will not receive no cost access to tracking data. … To get access to paid Tracking API or Tracking Webhook data, users will have to include a payment token including the EPA from their IP agreement in the Tracking API request or Tracking Webhook Subscription.”

[^25]: [PTR2 FAQs](https://postalpro.usps.com/mnt/glusterfs/2025-12/PTR2_FAQs_v1.pdf#page=3), PDF page 3: “As of June 2025, package origin and destination details are no longer available in the PTR Tracking API through the Webtools API, Webhooks, USPS APIs v3.0, or USPS APIs v3r2. … There are many purposeful and accepted differences between the PTR Tracking API (Webtools and USPS APIs Tracking v3) and the modernized PTR Tracking API (Tracking v3r2). … Other tracking channels, like USPS.com and Informed Delivery, that are still using the official system of record v3 API will have some different messaging, information and sometimes events than v3r2.”

[^26]: [Publication 32: Glossary of Postal Terms](https://postalpro.usps.com/mnt/glusterfs/2016-04/pub32_glossary.pdf#page=234), PDF page 234: “A suite of application program interfaces (APIs) that enables customers to integrate USPS shipping services into their e-commerce Web sites, call centers, or back-office systems.”

[^27]: [API Tech Sheet](https://postalpro.usps.com/mnt/glusterfs/2024-06/USPS%20APIs%20Tech%20Sheet%20.pdf#page=2), page 2: “The API calculates postage based on package attributes, applies rate, ensures product availability, standardizes addresses and generates the required Shipping Services File ensuring USPS compliance. … Create international outbound shipping labels and customs forms for packages. … The mailer ID used to create the tracking number and generate manifest files … Payer and label owner roles are required, the remaining roles are optional. … The platform used to create labels … By default, Commercial rates are applied. … Access USPS contract rates by applying an authorized USPS payment account or permit within the payment account end point. … Who is paying the postage”

[^28]: [Publication 199: Intelligent Mail Package Barcode (IMpb) Implementation Guide for Confirmation Services and Electronic Payment Systems](https://postalpro.usps.com/mnt/glusterfs/2026-07/Pub%20199_v35_07022026.pdf#page=473), page 474: “The electronic file containing all manifest and payment information.”

[^29]: [PostalPro: Tech Sheets for APIs, Click-N-Ship, and USPS Ship](https://postalpro.usps.com/tech-sheets): “Information on USPS offerings to help you streamline your shipping.”

[^30]: [USPS Ship Tech Sheet](https://postalpro.usps.com/mnt/glusterfs/2026-01/USPS%20Ship_Tech%20Sheet_V2.pdf#page=2), page 2: “USPS Ship customers have several options for generating package labels: using their own or commercial off-the-shelf software, connecting to Click N’ Ship, or connecting to USPS APIs. … Customers may create and submit a manifest file (SSF version 1.6, 1.7, or 2.0) including rate ingredients (weight, dimensions, packaging, entry) postage, and payment method for each package to USPS via PDX, SFTP, or AS2.”

[^31]: [PostalPro: Parcel Data Exchange (PDX) API](https://postalpro.usps.com/shipping/parcel-data-exchange-pdx-api): “The Parcel Data Exchange (PDX) provides parcel shippers an additional option to transmit Shipping Service Files and retrieve data extracts and error-warning reports through a secure web service interface rather than through the conventional FTP/SFTP method. … The PDX application is available free of charge for business customers and third-party vendors. … This application bypasses the Data Transfer Services (DTS) account configuration process, allowing a USPS Shipping customer to enroll online and begin shipping packages within the same day.”

[^32]: [USPS Ship Tech Sheet](https://postalpro.usps.com/mnt/glusterfs/2026-01/USPS%20Ship_Tech%20Sheet_V2.pdf#page=1), page 1: “Mailers submit package documentation, which is compared to physical package attributes from scan data, to determine an accurate postage amount.”

[^33]: [Package Tracking Options and Modernization](https://postalpro.usps.com/mnt/glusterfs/2025-09/Package%20Tracking%20Options%20Tech%20Sheet%20Sept%202025.pdf#page=4), page 4: “Customers enroll with USPS Data Transfer Services and either set up an SFTP account, an EDI integration, or use the PDX application to receive scan even extract files. … This option is not recommended for new users but is provided for experienced partners that prefer existing data transmission methods. … This subscription provides the tracking results at the time of the event and includes the entire event history, along with the fields available on the Tracking API. … A new subscription that streamlines the payload by delivering only the current event, rather than the entire event history. … This option also incorporates data fields that were previously exclusive to the Scan Event Extract file, including the container information and Mailer IDs.”

[^34]: [IMpb (Intelligent Mail® Package Barcode & IMmb (Intelligent Mail® Matrix Barcode) Verification Fact Sheet](https://postalpro.usps.com/mnt/glusterfs/2026-05/IMpb%20Fact%20Sheet%2020251003%20V37.pdf#page=2), PDF page 2: “Available for smaller mailers who do not use a software vendor and do not presort their mail. … Click-N-Ship (CNS)v2 / Enhanced Click-N-Ship allows submission of an electronic SSF with manifest, tracking, and postage payment.”

[^35]: [Domestic Merchant Returns API: User Guide](https://postalpro.usps.com/mnt/glusterfs/2026-07/Merchant%20Returns%20-%20Web%20Service%20and%20API%20Guide%20v2.6%202026-07-20.pdf#page=12), page 12: “The United States Postal Service (USPS®) Merchant Return web service provides free and easy generation of USPS® return labels for customers of merchants enrolled in the USPS® Merchant Return Program.”

[^36]: [PostalPro: Informed Delivery API (Application Programming Interface)](https://postalpro.usps.com/idapi): “The ID API provides Mailers and Shippers with the ability to integrate directly with the Informed Delivery application so they can manage interactive Informed Delivery campaigns for both Mail and Packages through their front-end applications.”

[^37]: [USPS APIs Terms and Conditions](https://postalpro.usps.com/mnt/glusterfs/2026-03/General_API_Terms_3-30-2026.pdf#page=2), PDF page 2: “The Service is an online platform, databases and portal that allows You to access data and request services from the USPS related to your mailing or shipping activity through the use of APIs and allows you to create shipping and mailing software or services.”

[^38]: [API Tech Sheet](https://postalpro.usps.com/mnt/glusterfs/2024-06/USPS%20APIs%20Tech%20Sheet%20.pdf#page=3), page 3: “Request domestic commercial or contract rates based on the characteristics of the package. … Request international commercial or contract rates based on the characteristics of the package. … Shipment Confirmation Acceptance Notice (SCAN) form allows integrators to link multiple domestic and international labels through one Electronic File Number (EFN) and physical SCAN Form (PS Form 5630). … The USPS scans this form at mailing acceptance to generate an acceptance tracking event for each linked label.”

[^39]: [USPS MCAT - TechSheet](https://postalpro.usps.com/mnt/glusterfs/2026-10/USPS%20MCAT%20TechSheet.pdf#page=8), page 8: “After generating an OAuth token, a Payment authorization token is needed to generate domestic and international labels. … Note: The PAYER and the LABEL_OWNER roles are required to pay for any label transaction. … All functionality currently available for the Labels API in Production will be available in MCAT. … However, a watermark will be applied to all label images generated in MCAT and there will be no actual postage charged to the mailers’ live payment accounts. … Performance/load testing is NOT supported in the MCAT environment. … If performance/load testing is needed, please submit a service request through Email Us to coordinate testing in the TEM environment.”

[^40]: [Merchant Onboarding and Authorization Tech Guide](https://postalpro.usps.com/mnt/glusterfs/2026-09/Merchant%20Onboarding%20Tech%20Sheet%209.15.26.pdf#page=13), page 13: “apis.usps.com”

[^41]: [DMM 509: Other Services](https://pe.usps.com/text/dmm300/509.htm): “Addresses API validates and corrects address information to improve package and mail delivery service using address data from the City State, ZIP + 4, Five-Digit ZIP, eLOT, DSF, and LACSLink databases, which are integrated into the Addresses API for a price charged monthly based on the tier, determined by the number of events.”

[^42]: [Notice 123: Price List (effective October 4, 2026)](https://pe.usps.com/text/dmm300/Notice123.htm): “Fee is monthly unless otherwise indicated. … Notice 123 • Effective October 04, 2026 … | Tier 1 - up to 2,000 Record Requests | $10.00 | … | Tier 2 - up to 10,000 Record Requests\* | 4.50 | … Per 1,000 Records. … | Tier 3 - up to 50,000 Record Requests\* | 4.25 | … | Tier 4 - over 50,000 Record Requests\* | 4.00 |”

[^43]: [Enterprise Payment System (EPS) FAQs](https://postalpro.usps.com/mnt/glusterfs/2026-03/EPS%20FAQs%20March%202026.pdf#page=2), page 2: “The Enterprise Payment System or EPS allows customers to pay for products and services through an Enterprise Payment Account (EPA) funded as an Automated Clearing House (ACH) Debit, which allows automatic withdrawal from your bank account, or Trust Account, which allows you to prefund your account.”

[^44]: [PostalPro: Business Portal (Formerly Customer Onboarding Portal)](https://postalpro.usps.com/BusinessPortal): “The United States Postal Service (USPS)Business Portal (COP) offers business customers a modern, streamlined way to create and manage a USPS business account set-up and onboard core services.”

[^45]: [USPS MCAT - TechSheet](https://postalpro.usps.com/mnt/glusterfs/2026-10/USPS%20MCAT%20TechSheet.pdf#page=5), page 5: “In the MCAT environment, customers can explore and validate USPS API integrations before moving to Production, including authentication, address validation, pricing, label creation, carrier pickup, and appointment workflows.”

[^46]: [USPS Ship Frequently Asked Questions](https://postalpro.usps.com/mnt/glusterfs/2026-01/20260106_USPS_Ship_FAQs_0.pdf#page=6), page 6: “Customers are encouraged to start in the API testing environment (CAT) for testing: https://developerscat.usps.com/. … To move to production, use https://developers.usps.com/ to get started.”

[^47]: [Tracking Access Control Tech Sheet](https://postalpro.usps.com/mnt/glusterfs/2026-03/Tracking%20Access%20Control.pdf#page=3), page 3: “Initiate request for tracking data access: Contact USPS via "Email Us" (https://emailus.usps.com/s/web-tools-inquiry) to initiate the order form and IP agreement process.”

[^48]: [Parcel Data Exchange (PDX) API Customer Guide](https://postalpro.usps.com/mnt/glusterfs/2023-09/PDX_API_User_Guide_09142023.pdf#page=13), page 13: “The PDX CAT environment is separate from PDX Production and provides an isolated testing environment or “sandbox” for customers to test PDX file uploads, lists and downloads without impacting any Production data. … A new username and password for the CAT environment are required to create the new CAT account. … Users will need to request new MIDs to use in the CAT environment. … separate from PDX Production and provides an isolated testing environment or “sandbox” for customers to test PDX file uploads, lists and downloads without impacting any Production data”

[^49]: [Parcel Data Exchange (PDX) API Customer Guide](https://postalpro.usps.com/mnt/glusterfs/2023-09/PDX_API_User_Guide_09142023.pdf#page=14), page 14: “This field can refer to one of the two supported environments: … “TEM” This is used for non-production data for testing purposes. … Overloading PDX with five or more manifest uploads per minute may cause your account to be deactivated.”

[^50]: [PostalPro: Testing Environment for Mailers (TEM) Using Mail.XML](https://postalpro.usps.com/certifications/testing-environment-mailers-tem-using-mailxml): “The Test Environment for mailers (TEM) is a test platform designed to allow mailers to test their ability to submit electronic mailing information such as Full Service (FS) mailings to the Postal Service.”

[^51]: [Parcel Data Exchange (PDX) Web Application User Guide](https://postalpro.usps.com/mnt/glusterfs/2023-08/PDX_Online_External_User_Guide_07262023.pdf#page=21), page 21: “Outbound files generated by Product Tracking and Reporting (PTR) are shown in the following table.”

[^52]: [PTR2 FAQs](https://postalpro.usps.com/mnt/glusterfs/2025-12/PTR2_FAQs_v1.pdf#page=4), PDF page 4: “Mailers must use versions 1.6, 1.7 or 2.0”

[^53]: [Package Tracking Options and Modernization](https://postalpro.usps.com/mnt/glusterfs/2025-09/Package%20Tracking%20Options%20Tech%20Sheet%20Sept%202025.pdf#page=3), page 3: “We recommend new businesses integrate with our Webhooks and API options for best results. … Choosing the preferred tracking tool may depend on the business need … Best for: Businesses or developers who want intermittent tracking status updates to integrate tracking into their own applications or websites and can’t store USPS tracking events in their system. … If you plan to build and maintain your own dataset of package tracking history, then we recommend the webhook subscription service. … Our recommendation is to start with Tracking 3.2, which will be available August 15, 2025. … USPS plans to sunset Webtools and Tracking 3.0 in 2026. … The new Subscriptions Tracking 3.2 specification can be found here. … In addition to updates to the existing Tracking Subscription, there is a new Detailed Scan Event Subscription.”

[^54]: [Tracking Access Control Tech Sheet](https://postalpro.usps.com/mnt/glusterfs/2026-03/Tracking%20Access%20Control.pdf#page=9), page 9: “Tracking 3.0 Modernization API Specs (also referenced as Tracking 3.2)”

[^55]: [Publication 199: Intelligent Mail Package Barcode (IMpb) Implementation Guide for Confirmation Services and Electronic Payment Systems](https://postalpro.usps.com/mnt/glusterfs/2026-07/Pub%20199_v35_07022026.pdf#page=66), page 67: “This file contains every scan event that occurs on every package that the mailer included in the Shipping Services file.”

[^56]: [Merchant Onboarding and Authorization Tech Guide](https://postalpro.usps.com/mnt/glusterfs/2026-09/Merchant%20Onboarding%20Tech%20Sheet%209.15.26.pdf#page=8), page 8: “will take the user to Click-n-Ship v2 to print labels.”

[^57]: [Domestic Merchant Returns API: User Guide](https://postalpro.usps.com/mnt/glusterfs/2026-07/Merchant%20Returns%20-%20Web%20Service%20and%20API%20Guide%20v2.6%202026-07-20.pdf#page=61), page 61: “The USPS Label Broker® will generate a unique code to identify the saved label.”

[^58]: [Publication 205 Electronic Verification System (eVS®) Business and Technical Guide](https://postalpro.usps.com/mnt/glusterfs/2024-07/eVS_pub205_July_2024_0.pdf#page=29), page 21: “where shippers can manage their mailing activity”

[^59]: [USPS APIs Terms and Conditions](https://postalpro.usps.com/mnt/glusterfs/2026-03/General_API_Terms_3-30-2026.pdf#page=11), PDF page 11: “You agree that the Postal Service may revoke your credentials and/or deny you access to the Services for any breach or suspected breach of any of the terms in this agreement or any activity that is fraudulent or suspected to be fraudulent.”

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Unofficial. Not affiliated with or endorsed by the United States Postal Service. This is https://postalref.com/guides/shipping-apis as Markdown.