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How to Set Up USPS Shipping

Updated
Feature Availability User Permissions Time to Complete Skill Level
US stores on Launch, Grow, Scale and the free trial Store owner, or a team member with Store settings & administration access (to set up) and Orders access (to buy labels) About 15 minutes Intermediate

Summary

Overview: US stores can ship with USPS by connecting their own USPS Business Account. Customers see live USPS rates at checkout, and you buy and print the shipping label from the order. USPS charges the postage to your own USPS payment account. Prosperna has no USPS account of its own, so USPS only appears at checkout once you connect yours.

Prerequisites:

  • A US store on Launch, Grow, Scale or the free trial.
  • A store location with a US address and a 5-digit ZIP code (see "How to Add Your Store Location"). USPS rates and labels use this address as the sender.
  • A USPS Business Account, with:
    • your CRID (Customer Registration ID)
    • your Mailer ID (MID), 6 or 9 digits, and a Manifest MID if you have a separate one
    • an EPS (Enterprise Payment System) or Permit imprint payment account, and its account number

Step-by-Step Instructions

Step 1: Open the USPS connection section

  1. In the sidebar, click Settings, then Shipping.
  2. Scroll below the shipping cards to Connect your own USPS account. This section only appears for US stores.

Step 2: Find your USPS details

The section explains where to find each detail in the USPS Business Portal (cop.usps.com), under My Account:

  • your CRID is listed with your business location
  • your Mailer IDs are under the Mailer ID tool
  • your Enterprise Payment Account is under My Payment Accounts

Step 3: Connect your USPS account

  1. Enter your CRID.
  2. Enter your Mailer ID (MID).
  3. (Optional) Enter your Manifest MID. Leave it blank if you only have one MID.
  4. Under Payment account type, choose EPS (Enterprise Payment System) or Permit imprint.
  5. Enter your Payment account number.
  6. Click Connect. Prosperna checks your account live with USPS before saving anything.
  7. When it works, you see USPS account connected.

USPS checks your payment account number, so a wrong number is refused right away. USPS does not check your CRID. Type it carefully: a wrong CRID only shows up when you buy a label.

Step 4: Check your connection

After you connect, the section shows:

  • a Connected badge and Your USPS account is verified and in use.
  • CRID and MID, showing only the last four digits
  • Payment account type. Your account number is never shown again.
  • Package tracking updates with an Automatic badge. It tells you how often Prosperna checks USPS for new scans and how many labels are being tracked. Click Check again to update it.

Step 5: Set up and switch on the USPS shipping method

  1. Under Prosperna Shipping, find the USPS card (Live USPS rates) and click Set Up.
  2. On the Settings tab, under Payment Option, tick at least one option that isn't greyed out. For USPS, Cash on Delivery and Cash on Pickup are greyed out.
  3. Click Save. You see Successfully set up shipping settings.
  4. Go back to Settings → Shipping and turn on the switch on the USPS card. You see Successfully updated shipping settings.

Step 6: Choose your USPS rates (optional)

  1. On the USPS card, click Manage, then the Rates tab.
  2. Under Who Pays for Shipping?, keep Customer.
  3. Under Shipping Fee Calculation, choose one of these and click Confirm in the Warning window:
    • Auto-Calculated by Courier: the customer pays the live USPS rate.
    • Courier Quote + Your Add-ons: the USPS rate plus a Markup % (0 to 100) and an extra fee you set per state. Type the markup and click outside the box to save it.
    • Flat Shipping Fee: your own rates per US state replace the USPS rate.

For how to set per-state fees and flat rates, see "How to Set Up Manual Shipping and Shipping Rates".

Step 7: See what your customers get at checkout

  1. Customers see USPS Ground Advantage: "Shipped via USPS. Your rate is calculated from your delivery address, and you'll receive a tracking number once your order ships."
  2. The rate appears once the customer enters a valid 5-digit ZIP code.

Step 8: Buy the shipping label

  1. In the sidebar, click Orders, then open the USPS order.
  2. In the Delivery section, click Buy Shipping Label. The button is greyed out until the order is paid ("You can buy a label once this order is paid.").
  3. In the Buy USPS shipping label window:
    • Check Weight (lbs). It's filled in from the order's product weights. Change it if your package weighs more.
    • (Optional) Enter Length (in), Width (in) and Height (in). If you leave them blank, a standard package size is used.
  4. Click Buy label. You see USPS label purchased. USPS charges the actual postage to your own account, which can differ from the rate your customer paid.
  5. Click Download label (PDF) to open the label and print it.

The Delivery section now shows Tracking: with the tracking number and Postage paid: with the amount.

Step 9: Track the package

  • Prosperna checks USPS for new scans on every label you buy, and the order status updates on its own.
  • To check right away, click Refresh status on the order.
  • If the order shows a Tracking Link ("Track your USPS package here"), click here to follow the package.

Step 10: Cancel a label (optional)

You can cancel a label only before USPS scans the parcel. After the first scan, Cancel label disappears.

  1. On the order, click Cancel label.
  2. In the Cancel USPS label window, read the message: USPS voids the label and refunds the postage to your account, and the tracking number stops working.
  3. Click Cancel label. You see USPS label cancelled. USPS will refund the postage. You can buy a new label afterwards.

Step 11: Disconnect your USPS account (optional)

  1. In Connect your own USPS account, click Disconnect.
  2. In the Disconnect USPS account window, read the message: USPS stops appearing at checkout and your account details are removed. Labels you already bought stay available.
  3. Click Disconnect. You see USPS account disconnected. The USPS shipping method is switched off at the same time.

You can connect again at any time by repeating Step 3.

Verify It Worked

Success criteria:

  • You saw USPS account connected., and the section shows the Connected badge.
  • The USPS card's switch is on.
  • On your store's checkout page, USPS Ground Advantage appears with a rate after you enter a US address with a 5-digit ZIP code.
  • On a paid USPS order, Buy label gives you USPS label purchased. and a tracking number.

Troubleshooting

Common errors

  • "Please fill in your CRID, Mailer ID, and payment account number.": one of the required boxes is empty.
  • "CRID must be digits only, up to 15 of them.": remove any letters, spaces or dashes from your CRID.
  • "Mailer ID must be exactly 6 or 9 digits." or "Manifest MID must be exactly 6 or 9 digits.": check the number in the USPS Business Portal.
  • "USPS rejected the payment account details (CRID / MID / account number): …": USPS didn't accept your details, and nothing was saved. Check them and try again.
  • "USPS is not available right now. Please try again later." or "We could not verify your USPS account right now. Try again in a few minutes.": the problem is on the USPS or Prosperna side, not your details. Try again later.
  • "Failed to connect your USPS account." or "Failed to disconnect.": try again.
  • "We could not load your USPS connection. Reload to try again.": reload the page.
  • "Connect your USPS account before enabling USPS shipping.": connect your USPS account (Step 3) before you switch on the USPS card.
  • "Please select at least one payment option." when you save the USPS card: tick an option that isn't greyed out. If every option is greyed out, you can't save the card yet. Contact support.
  • A customer sees "Enter a valid 5-digit ZIP code to get a USPS shipping rate.": the customer needs to enter a full 5-digit ZIP code.
  • A customer sees "USPS shipping is not available for this address right now. Please choose another shipping method or try again later.": USPS couldn't give a rate. Check that your store location has a 5-digit ZIP code. If you use Flat Shipping Fee, checkout uses your own rates instead and doesn't show this.
  • "Enter the package weight in pounds.": enter a weight above zero in Weight (lbs).
  • "Your store location needs a US address with a 5-digit ZIP code before you can buy a label.": fix your store location's address and ZIP code.
  • "The delivery address needs a street address and a 5-digit ZIP code.": update the customer's shipping address on the order.
  • "This order already had a label, so we reused it. You were not charged twice.": the order already had a label, so no new postage was charged.
  • "A label purchase for this order is already in progress. Wait a moment and refresh.": wait, then refresh the order.
  • "We lost contact with USPS while buying this label, so we cannot tell whether it was bought…": don't buy again from this order. Contact support first, or you might be charged for a second label.
  • "Could not open the label.": the label couldn't be opened. Click Download label (PDF) again. If your browser blocks pop-ups, allow them for Prosperna.
  • "USPS has no tracking information for this label yet. Scans appear after the parcel is accepted at a Post Office.": hand the parcel to USPS, then check again later.

Limitations & considerations

  • USPS is for US stores only. Philippine stores don't see it.
  • Customers always see USPS Ground Advantage. You can't change the mail class or save a default package size from the dashboard.
  • Cash on Delivery and Cash on Pickup can't be used with USPS.
  • Your USPS account pays the real postage. Any difference between that and what your customer paid is yours.
  • USPS labels don't use Shipping Credits.

Next Steps & Related Resources

Need more help? For more information and assistance, please send an email to support@prosperna.com.

Last Updated: 10/09/2026