Allow Custom Apps in Shopify
1. Enable Custom Apps
Log in to the dashboard and go to:
"Settings"
"Apps and Sales channels"
"Develop apps"
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2. Allow custom app development
3. Confirm
... for ... reasons
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All Done!
If you are our client, please let our dev team know that you're all set.
If you're a developer, please review the "Create Custom Apps in Shopify" article