How to connect a subdomain of an existing Shopify store to a custom app? Now getting 301.

Shopify Apps

Topic summary

A script intended to read products from a Shopify store returns a 403 Forbidden error (HTTP access denied).

The poster thinks the issue may relate to domain setup in Shopify Admin but wants to avoid using the live store URL. They ask how to connect a subdomain of an existing, not-yet-live store (e.g., dev.store123.com) to Shopify Admin instead.

They have created a custom app and obtained most credentials, but suspect something is missing and request guidance on completing the setup to successfully read products.

Status: No solutions or replies yet. Open questions include whether connecting a subdomain is necessary for Admin API access and which specific app credentials/permissions are required to resolve the 403 error.

Summarized with AI on January 7. AI used: gpt-5.
1

Hi, I have a simple script that reads out the Shopify products under my account. But when I run it, I get a 403 forbidden error.

I read that I need to connect my domain to the Shopify admin, but I don’t want to use the live store URL. Instead, I want to use a subdomain of an existing store that is not yet live.

For example, if my store URL is shopify.com/store123, and my subdomain is dev.store123.com, how can I connect it to the Shopify admin?

I also created a custom app with almost all the credentials available. But I think there might be something missing.

Can anyone help me with this