Start with the shopping journey. Document how a visitor discovers products, chooses a variant, changes quantities and completes an order. Verify which Shopify APIs and permissions support each step before designing around an assumption.
Catalogue details matter
A product is more than a title and image. Consider availability, variant combinations, tags, collections and fields that are specific to the merchant. Use realistic sample data with long names and missing optional images.
Keep pricing authoritative
Display values returned by the commerce backend and refresh them at meaningful transitions. Do not calculate the final payable amount from an outdated product list. Taxes, shipping and discounts belong to the supported checkout flow.
Design account recovery
Plan expired sessions, sign-in failures and order-history states. Explain what can be used as a guest and which actions require an account.
Release in stages
Verify one complete order flow in a development store before expanding templates. Build acceptance criteria around observable behavior. Keep payment credentials and private API secrets out of the mobile binary.