Stacking Discount Codes, Volume Discounts, and Shipping Discounts

Shopify Discussion
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Topic summary

A one-product store is experiencing checkout abandonment due to discount stacking errors. The store currently offers free shipping over $75 and volume-based product discounts (24-28% off) via the Rapi app, but customers cannot apply additional promotional codes from Klaviyo or affiliate programs.

Core Issue:

  • Shopify prevents stacking multiple product discounts on the same item
  • Klaviyo auto-generated codes lack “Combinations” settings by default

Proposed Solutions:

Workarounds for Klaviyo codes:

  • Manually create combinable discount codes and upload to Klaviyo
  • Use third-party apps to enable combination functionality

Recommended discount structure:

  • Configure Rapi volume discount as an order discount (not product discount) to enable stacking
  • Set all discounts to combine: order discounts + product codes + shipping
  • This allows multiple order discounts to apply simultaneously per Shopify’s rules

Status: The original poster is considering switching to order-based volume discounts to resolve the conflict. Note that Shopify’s Discounts Allocator Function API (currently in developer preview) may eventually provide native stacking capabilities.

Summarized with AI on October 31. AI used: claude-sonnet-4-5-20250929.
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Hi @cupofjoe12 , this is an interesting situation.

From what I’ve read through, it seems like you have the following configuration - please correct me if I’m wrong.

  1. Free shipping above 75$ - is this configured through Shopify admin settings (or) as a Shipping discount in the admin?
  2. Order volume discount using Rapi - (First item is full price, two or more is 24% off, four or more is 28% off) - configured as product discounts.
  3. Order discounts using Klaviyo
  4. Affliate marketing discounts

By default, discounts created by Klaviyo are not combinable with other discounts in the cart. You can overcome this in two possible ways..

  1. Create your own set of unique codes that are combinable and then upload into Klaviyo for use (guide)
  2. Use an app to make discounts created by Klaviyo combine with others. There are many apps that do just this

[CODE] couldn’t be used with your existing discounts.

This could be because you are trying to stack multiple product discounts on the same product, which is not supported by Shopify and only the best discount will apply to the product in cart.

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What I would suggest getting all your discounts to work in harmony would be to

  1. (product) Set up the volume discount (Rapi) as a product discount and allow combine with shipping & orders
  2. (order) Setup Klaviyo / Affliate apps to combine with product and shipping discounts
  3. (shipping) Shipping discount setup in admin to combine with product and orders

The alternate would be to make the volume discount from Rapi as an order discount and then allow stacking of discounts. This will work because “Multiple order discounts can apply to the same order.” as per Shopify’s documentation.

Hope this helps :slightly_smiling_face: