Define the account and source behind the loyalty card
Start with the approved loyalty program and how customers identify their account. Decide which record supplies the card state and which source confirms a qualifying purchase or staff action. A mobile screen should present that state rather than calculate an independent balance from visual markers alone. First check whether the existing POS or loyalty provider already supplies the required customer view and staff process. If a custom layer is justified, assess sample purchase events, stable event identifiers, cancellations and the provider's correction behavior before choosing the update model. The grocer owns the offer rules and customer-facing program language. Campaign discovery and branch-specific offer publishing can be scoped separately from this purchase-source and confirmation work.
