How can I block certain postcodes before order placement?

Shopify Discussion

Topic summary

Goal: prevent customers from placing orders to certain UK postcodes before payment.

Current constraints:

  • Delivery profiles can’t be used because Shopify doesn’t parse UK postcode formats as needed.
  • Shopify Flow appears to trigger only after an order is placed, so it can’t block at checkout.
  • Merchant prefers not to install additional apps and cites limitations with single-origin shipping.

Request:

  • Seeking a native/built-in method to block restricted postcodes prior to payment or confirmation.

Status:

  • No solution or workaround provided in the thread yet; the question remains open.
Summarized with AI on January 1. AI used: gpt-5.
1

Correct me if I am wrong, but am I correct in thinking there’s no way to stop an order before payment currently?

Essentially I need to block certain postcodes. Shopify doesn’t understand UK postcodes so I can’t do it with the delivery profiles.

I can’t see how to do it with Shopify Flow until the order is placed.

Is there anything I’m missing? I have no desire to add more apps since Shopify won’t let me use single origin shipping