When the Auto-Apply feature is enabled, the
applyPromotionCode(promocode) order method behaves in the following manner:
If the promotion code that you are applying delivers a better value to the shopper than the exclusive promotion, the promotion code is accepted and the exclusive promotion is removed.
From both manually and automatically applied promotions, the best combination of promotions is computed and applied to a transaction.
When troubleshooting auto-apply promotions, the following fields in the
promocode JSON object results can be useful:
is_auto_applied: determines if the promotion code is applied manually or automatically.
applicability_status: determines if the promotion code is actually applied to the sales order or not.
applicability_reason: determines the reason a promotion code was not applied.