About courier reference codes
What is a Courier Reference Code?
When you create a courier in Zonal, you need to enter a Courier Reference Code.
This code is the unique identifier Zonal passes to Shopify so Shopify knows which courier to offer to the customer at checkout.
The code can come from a third-party provider, such as a courier company or an EPOS system, but it does not have to. You can also create your own code as long as each courier has a different one.
The Courier Reference Code is used to identify the courier in Shopify. It should be unique for every courier you set up in Zonal.
When you need to enter it
In Zonal, go to the screen where you add a new courier and complete the courier details.
In the Courier Reference Code field, enter the identifier you want Shopify to use for that courier.
Save the courier once you have confirmed the code is unique and matches the courier you want Shopify to offer.
When you may be asked to update it
If you edit a courier that already has a Courier Reference Code, Zonal may show a prompt asking you to update it if another courier is already using the same code.
This prompt is there to help prevent duplicate courier identifiers.
If two couriers share the same Courier Reference Code, Shopify may become confused about which courier to show and can offer the wrong courier in some situations.
Best practice for choosing a code
Use a code that is unique to that courier only.
If you already have a reference from a courier company or EPOS system, you can use that.
If you do not have an existing reference, create your own naming pattern and keep it consistent.
Do not reuse the same code across multiple couriers, even if the courier names are similar.
Why unique codes matter
Shopify uses the Courier Reference Code to decide which courier option to offer to the customer.
If more than one courier shares the same code, Shopify may not be able to reliably tell them apart. That can lead to the wrong courier being shown during checkout or in other delivery selection scenarios.
If you see a duplicate code prompt
Review the Courier Reference Code on the courier you are editing.
Check whether another courier in Zonal is already using that same code.
Update the code so it is unique.
Save your changes.
If the code came from a third-party system, make sure the updated value still matches the identifier you expect Shopify to use.
Quick checklist
Every courier has a value in Courier Reference Code.
No two couriers use the same code.
The code matches your intended courier mapping in Shopify.
Any third-party reference you use is entered exactly as needed.