This article explains how Negotiated Service Agreement (NSA) customers use a USPS Enterprise Payment Account (EPA) with your ShipStation account through Stamps.com. To do so, you will need to create an EPA within the USPS Business Portal (formerly the Customer Onboarding Portal (COP)).
New to the USPS Business Portal and NSA Rates? Please see our page for New Customers: Link Your USPS Business Account to ShipStation.
Already have a USPS Business Portal and NSA Rates? See our page for Existing Customers: Link Your USPS Negotiated Service Agreement (NSA) Account.
This table defines important abbreviations used in this article.
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Abbreviation |
Term |
Definition |
|---|---|---|
|
NSA |
Negotiated Service Agreement. |
A customized, contractual agreement between the Postal Service and high-volume mailers that provides discounted rates or flexible classifications in exchange for increased mail volume. |
|
EPA |
Enterprise Payment Account. |
The single, centralized account (the 10-digit number) that a customer creates within the EPS platform. Starting early 2026, this number will be mandatory for NSAs to link their USPS contract rates to their Auctane account. Used for:
|
|
EPS |
Enterprise Payment System |
The USPS payment platform that manages all business postal transactions. The system is responsible for hosting and managing the individual EPA. |
|
ACH |
Automated Clearing House |
An electronic network for processing bank-to-bank transfers, typically used for low-cost, direct payment from a checking or savings account. ShipStation offers this payment method free of surcharge to customers. |
|
CC |
Credit Card |
Credit Card is available as an optional payment. |
What is an EPA?
An Enterprise Payment Account (EPA) is a payment account you create directly with USPS. It is part of the USPS Enterprise Payment System (EPS).
Understanding Your Enterprise Payment Account (EPA) and Payment Processing Options
When you set up your USPS Business Account within the USPS Business Portal, you will be asked to create an Enterprise Payment Account (EPA) with USPS. This EPA is required to purchase USPS labels within Auctane with your USPS rates.
How does ShipStation use your EPA?
After you create your EPA with USPS, you’ll return to ShipStation and enter your EPA number in our system. In most cases, ShipStation will process your payments for USPS labels. This means you’ll see your available balance within your ShipStation account, and ShipStation will handle all payment processing for your USPS labels on your behalf.
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If you have never printed USPS labels with NSA rates before, you must first create an account with Stamps.com or ShipStation that uses an NSA Promo Code. Please contact your USPS Sales Representative to obtain an NSA Promo Code.
During registration, input this promo code, then complete your account registration. Then proceed to the Step-by-Step connection guide below.
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If you have connected your NSA rates to your existing Stamps.com or ShipStation account, log in to your account on ShipStation.
Dashboard Banner: A banner titled Connect your USPS business account to Stamps.com to access NSA rates will also persist at the top of your screen. This banner will remain visible throughout the app until the process is finished.
Locate and click the new See Instructions button that appears on your dashboard.
Click Link your business account to begin the process of securely connecting your USPS account.
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To begin, click See Instructions.
Clicking See Instructions from either the pop-up or the banner will open a new browser tab to the Stamps.com guidelines.
Automatic Login: You will be automatically authenticated into the Stamps.com interface based on your active ShipStation session. No additional login is required.
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Follow the on-screen prompts and complete the flow within the Stamps.com tab to finalize your Customer Onboarding Portal steps.
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To obtain an NSA (Negotiated Service Agreement) Promo Code, you must contact a USPS Sales Representative directly and follow their formal negotiation process. NSAs are personalized agreements for high-volume business mailers, and promo codes are not publicly available.
How to Contact a USPS Sales Representative
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Use the Contact Directory on PostalPro. The USPS website for commercial mailers has a contact directory with specific phone numbers and email addresses for various services, including the Mailing and Shipping Solutions Center (MSSC) for commercial customers.
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Email the Pricing Strategy team. For initial inquiries, send an email to nsa@usps.com to begin the process. The email should include a proposal with reasons for requesting an NSA.
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Call the Pricing Strategy team. You can contact the Pricing Strategy division directly by calling 202-268-7284.
Prepare Your NSA Proposal
Negotiated Service Agreements are not instant discount codes but are the result of a formal process. Your request will require a detailed proposal outlining the following:
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The reasons for seeking an NSA.
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Supporting documentation.
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Information that meets the general requirements of the NSA program.
Before having a substantive discussion, you will be required to sign a nondisclosure agreement.