USPS Shipping Rates Not Showing or Intermittent at Checkout

USPS Shipping Rates Not Showing or Intermittent at Checkout

If USPS shipping rates are not appearing at checkout, appear inconsistent, or occasionally fail to load, this is typically related to how the United States Postal Service (USPS) API handles request limits.

Why This Happens

USPS provides real-time shipping rates through their API. While limits are not always formally published, USPS may restrict or throttle requests when too many are sent within a given period.

In Spirit Sale, this can occur more easily because:
  1. Each checkout session can generate multiple rate requests
  2. Refreshing checkout or updating an address triggers additional requests
  3. Spirit Sale uses the same USPS API credentials across multiple stores
  4. Activity across those stores contributes to a shared request limit
Info
 Based on industry experience and USPS API behavior, most accounts operate around a default limit of approximately 60 requests per hour, unless a higher limit has been approved.

When request volume exceeds this level, USPS may:
  1. Return no available shipping methods
  2. Return incomplete or delayed results
  3. Temporarily reject requests

Important to Know

  1. This behavior originates from USPS and is outside of Spirit Sale’s control
  2. All stores using the same USPS credentials contribute to a shared usage limit
  3. This means limits can be reached even if a single store has moderate traffic
  4. The issue is often temporary and resolves automatically

Common Scenarios

  1. Customers reload refresh the checkout page multiple times
  2. Customers enter or modify their address repeatedly
  3. Your store(s) have multiple customers checking out at the same time within a short span of another (Generally within an hour)

What You Can Do

  1. Retry after a short wait - In many cases, waiting briefly and refreshing checkout will allow USPS rates to return.
  2. Provide backup shipping options - To prevent checkout disruption, consider enabling Flat rate shipping or free shipping options.
  3. Request a higher USPS API rate limit - If this issue occurs frequently, your USPS account may be reaching its default usage limits. You can contact USPS API support to request an increase by emailing apisupport@usps.gov. 
Alert
Please note: Approval of increased limits is determined by USPS and is not guaranteed.

    • Related Articles

    • Updating Your USPS Credentials in Spirit Sale (Migration to New USPS APIs)

      Who Does This Apply To This information only applies to Spirit Sale stores still using the older USPS Web Tools (Legacy) API for live shipping rates. You do NOT need to follow this guide if: You don't use USPS for shipping. You already migrated to ...

    • How to Create USPS API Credentials

      Overview This article walks you through the steps for creating USPS API credentials using the USPS Developer Portal↗. These credentials allow your your Spirit Sale stores to securely access USPS APIs for services such live shipping rates. Steps to ...

    • How to enable offline payments

      First, enable Offline Payment as a payment method, if not already enabled. From the Spirit Sale dashboard go to Setting --> Payment Methods. Click the Offline Payment box. Enable the Active toggle, then press Update. Now, to enable Offline payments ...

    • How to Set Up Your Stripe API Keys With Spirit Sale

      Overview Spirit Sale integrates directly with Stripe to process payments. To connect your store, you’ll need your live publishable key and live secret key from Stripe. Important Notes: Only standard live keys are supported. Restricted keys will not ...

    • Labels or Designs Not Showing

      Sometimes a stores background and text color are the same or very close. This similarity in color would cause text or icons against the background not to be visible. Changing the store's Font/Icon color to something darker will resolve this. To ...