To show USPS rates only when customers select shipping in our widget, we recommend integrating USPS in the Rates tab of Zapiet - Pickup + Delivery.
For any questions about the rate value, please contact USPS—we only show the rates they generate.
Integration steps will be slightly different, depending on the Zapiet - Pickup + Delivery rates version that you're using:
Requirements
All products that require shipping need to be marked as a Physical product in Shopify.
You will need to have an active USPS account and your username.
Log in to the USPS Developer Program website using the username and password for your USPS Solutions for Small Business account. Select your account number from the dropdown list.
Enable USPS with Zapiet - Pickup + Delivery rates
Our latest rates feature allows merchants to use Zapiet - Pickup + Delivery rates without needing access to Shopify Carrier Service API. Take a look at our Zapiet - Pickup + Delivery rates article for more details.
To integrate USPS with Zapiet - Pickup + Delivery rates, please add USPS in Shopify. Any rates in Shopify that are not set up within Zapiet - Pickup + Delivery will be seen as shipping rates. This will ensure that your customers see discounted rates provided by USPS.
Disable USPS with Zapiet - Pickup + Delivery rates
If you no longer want to use calculated shipping by USPS, then you can disconnect your USPS carrier account from your Shopify admin.
Enable USPS rates with Carrier Service API
When using Zapiet - Pickup + Delivery with Carrier Service API, our app does not have the ability to show discounted Shopify rates—only Shopify can offer discounted rates. Please use our latest rates feature to take advantage of the discounted Shopify rates. Take a look at our Zapiet - Pickup + Delivery rates article for more details.
In Zapiet - Pickup + Delivery, click Rates.
Go to the Shipping section and click Advanced Options.
Find USPS and click Add carrier.
Enter your username and tick Enable USPS rates.
Add handling fees if needed, and click Save.
Your USPS rates should now be generated through Zapiet - Pickup + Delivery when your customers select shipping in the widget—you can now test them.
Disable shipping rates
If you have added shipping rates in Zapiet - Pickup + Delivery, we recommend removing them, so you can only show USPS rates.
In Zapiet - Pickup + Delivery, click Rates.
In the Shipping section, click Edit next to your shipping zone.
Click Delete zone.
Click Confirm, delete this zone to delete this shipping zone.
Your Zapiet - Pickup + Delivery shipping rates are deleted now, and the only rates generated for shipping will be coming from USPS.
Prevent duplicate rates
When your USPS rates are generated through Zapiet - Pickup + Delivery, we recommend removing USPS as the carrier from Shopify shipping and delivery settings.
In Shopify Settings, click Shipping and Delivery, then click General shipping profile.
Delete USPS as a carrier if it's added to your domestic shipping zone.
Click Save.
Only Zapiet - Pickup + Delivery should be added as a carrier under your domestic shipping zone. Then, our app can control which rates to show at checkout, depending on the checkout method selected in our widget.
Disable USPS rates
If you want to stop using USPS with Zapiet - Pickup + Delivery, you can disable the rates.
In Zapiet - Pickup + Delivery, click Rates.
In the Shipping section, click Edit next to USPS.
Untick Enable USPS rates.
Click Save.
USPS rates will no longer appear when selecting delivery or shipping in our app.
Make sure to add your delivery and shipping rates within our app or Shopify, so that your customers can check out. You can take a look at our Rates setup guide for more information.
Limitations
When using a Last mile delivery service or an integrated carrier for rates, Shop Pay is the only supported Express checkout method.
Other methods, such as Apple Pay and Google Pay, will show no rates and customers will be unable to checkout.
Troubleshooting
If you're not seeing USPS rates:
Check if the correct credentials are added—make sure you're adding the correct username from your USPS account.
For any questions about USPS functionality (rate values, tracking), please contact USPS technical support at 1-800-344-7779.