How to integrate dynamic shipping rates with our custom checkout extension?

Extensions
1

Hi,

I’m developing a custom app to connect Shopify store to a delivery company. I made a checkout extension that lets customers select their delivery city from a dropdown.

I want to show shipping rates based on the selected city. What’s the best way to do this?

Specifically:

  • Can our checkout extension update the shipping address city field to trigger carrier rate recalculation?

  • What plan do merchants need to be on for this to work?

  • Are there any limitations we should know about?

Thanks in advance.

2

HI，
you need to create a carrier service that provides real-time shipping rates to Shopify. Carrier services provide real-time shipping rates from external providers like FedEx, UPS, or custom shipping solutions. The carrier service connects to your external shipping rate calculation system through a callback URL
When customers reach checkout, Shopify sends order details to your callback URL and displays the returned shipping rates. The service must be active to provide rates during checkout.
so you dont need to customize a checkout extension to do so .

you shop plan must be advanced or plus.