What is a discount effect?

A discount effect defines how a discount (coupon, cart promotion, referral incentive, loyalty reward) is applied to a customer’s order/cart. Instead of simply specifying “10% off” or “$5 off,” the discount effect describes which parts of the cart will be discounted (whole order, selected items, free items, etc.) and how the discount amount is distributed across those parts.

Using discount effects allows brands to precisely control discount logic beyond flat reductions, enabling complex promotions that account for product mix, cart composition, item quantity, and business rules.

Core discount effects in Voucherify

Here are the primary effects you can apply (depending on discount type), and what they do:

• APPLY_TO_ORDER: Discount applies to the entire order total (cart-wide discount).
• APPLY_TO_ITEMS: Discount applies only to selected items or collections (product-level discount).
• APPLY_TO_ITEMS_PROPORTIONALLY: Discount is split across chosen items proportionally based on their share of total item value. Useful when discount should affect only certain items but reflect their price weight.
• APPLY_TO_ITEMS_PROPORTIONALLY_BY_QUANTITY: Discount is split across eligible items proportionally by quantity (rather than value), giving equal unit-based discount.
• APPLY_TO_ITEMS_BY_QUANTITY: Applies the discount to each eligible unit individually (e.g. fixed-amount off per item unit).
• Unit-based / “Free Items” Effects: Instead of discounting price, your discount can add free product units or replace items, e.g.:
  • ADD_MISSING_ITEMS: Adds free units only if the related items are missing in cart.
  • ADD_NEW_ITEMS: Always adds new free units as part of the discount.
  • ADD_MANY_ITEMS: Adds multiple free items when a promotion tier calls for it (e.g. “Buy 2 get 2 free”).

Beyond product discounts, discount effects can also be used for:

• Free shipping: default-included via built-in “shipping” item discounting.

Why discount effects matter?

Discount effects give you control and flexibility for real-world promo scenarios. They allow your incentive engine to:

• Target only certain products or categories with discounts (not whole cart).
• Manage complex bundle or BOGO promotions by adding or adjusting items dynamically.
• Split discounts fairly across multiple products in a cart depending on value or quantity.
• Protect margin by capping discount per unit or per cart line.
• Combine multiple discount triggers (cart-level, item-level, loyalty, referral) without conflict.

How Voucherify uses discount effects?

In Voucherify, when you create a discount, whether a code campaign, referral award, or in-cart promotion, you attach a discount effect to tell the system how to apply it. The system merges this with validation rules and metadata, then at redemption/checkout time:

• Evaluates which items or carts are eligible.
• Computes the discount allocation according to the effect logic.
• Adjusts cart pricing or adds free items accordingly.
• Validates all caps, exclusions, and constraints.