Function API Delivery customization issue

Retired Boards Appdev Functions

Topic summary

A developer is experiencing a bug with Shopify’s Delivery Customization Function API when hiding shipping rates based on address content (specifically “PO Box”).

Core Issue:

  • The function successfully hides all shipping rates when an address contains “PO Box”
  • However, when the address is changed or “PO Box” is removed, shipping rates don’t reappear
  • Rates only return after manually refreshing the checkout page

Key Details:

  • The function works correctly when hiding only 1 rate out of 2 available rates
  • Problem occurs specifically when hiding all shipping rates
  • Video example and request IDs provided for troubleshooting
  • Initially worked with address field changes, but now fails on both single-page and 3-step checkout

Current Status:

  • Shopify staff member (Nick_Wesselman) confirmed reproduction of the issue
  • Reported internally as a known bug: address changes are not re-triggering delivery customization functions
  • Awaiting resolution from appropriate team
  • Issue is impacting production users who had to switch from single-page to 3-step checkout as a workaround
Summarized with AI on November 13. AI used: claude-sonnet-4-5-20250929.
7

It was working with changing any value in inputs on customer information fields. I am 200% sure.

because we have 3 users they are using this function and right now they have to switch 3 step checkout after facing issue. they preferred one page checkout.