Shopify Bundles + Cart Transform: The Hidden Limitation Affecting B2B Stores

TL;DR: Shopify Bundles and the Cart Transform API currently conflict. When using the official Shopify Bundles app, any price modifications (via UpdateOperation) are ignored by the checkout. This means critical features like B2B wholesale pricing, VAT exemptions, and loyalty discounts will not work on bundle products. This is a known Shopify platform limitation with no current ETA for a fix, requiring merchants to use workarounds like catalog segmentation or manual adjustments.

Shopify Bundles have become a go-to solution for merchants looking to increase Average Order Value (AOV). Simultaneously, Shopify Functions, specifically the Cart Transform API, have become the gold standard for high-growth stores to handle complex pricing logic.

However, there is a significant “gotcha” that Shopify hasn’t widely documented: Shopify Bundles and Cart Transform functions currently do not work together.

If you are running a Shopify Plus store and rely on custom pricing logic for B2B or international customers, this limitation could be silently breaking your checkout experience.

What is Cart Transform?

The Cart Transform API is part of the Shopify Functions suite. It allows developers to programmatically “transform” the cart by merging products, expanding bundles, or—most importantly—modifying prices on the fly.

For Shopify Plus merchants, it is the modern replacement for Shopify Scripts. Common use cases include:

• B2B Pricing: Dynamically adjusting prices for wholesale customers.
• VAT Exemption: Removing tax for verified business customers in real-time.
• Loyalty Discounts: Applying specific price drops based on customer tags.
• Currency Adjustments: Fine-tuning prices for international markets.

The Problem: The “UpdateOperation” Conflict

The issue arises when a customer adds a Shopify Bundle (created via the official Shopify Bundles app) to their cart while a Cart Transform function is active.

Technically, the Cart Transform API uses an UpdateOperation to change the price of a line item. However, Shopify’s Bundles pricing system is currently “hard-locked.” When the system detects a bundle product, it prioritizes the bundle’s fixed pricing logic and completely ignores any price modifications sent by the Cart Transform function.

In short: If it’s a bundle, your custom pricing code won’t work.

Which Use Cases are Affected?

This limitation creates significant friction for stores that need more than “out of the box” pricing.

Official Shopify Standpoint

Shopify is aware of this conflict. It is currently categorized as a known limitation awaiting a major refactor of the platform’s core pricing engine.

While Shopify Functions are meant to be the future of extensibility, the Bundles logic currently sits in a separate layer that the Cart Transform API cannot yet override. There is currently no official ETA for a fix, leaving developers and merchants to find their own solutions.

Possible Workarounds

Until Shopify releases a native fix, here is how you can manage this limitation:

For Merchants

• Segment Your Catalog: Avoid offering Shopify Bundles to your B2B or wholesale customer segments. Use standard products for these groups instead.
• Manual Adjustments: If a B2B customer buys a bundle, be prepared to issue a manual credit note or refund for the tax/discount difference.
• Alternative Bundling: Consider using “Draft Orders” or “Manual Bundles” (individual items added to the cart) rather than the official Shopify Bundles app if price manipulation is required.

For Developers

• Bundle Detection: Update your Cart Transform logic to detect if a product is a bundle. If it is, you can trigger a frontend warning informing the user that discounts do not apply to bundles.
• Post-Purchase Webhooks: Use webhooks to detect when a bundle has been purchased by a B2B customer and automatically generate a refund for the VAT portion.

Conclusion

The Shopify Bundles and Cart Transform conflict is a frustrating hurdle for stores moving toward advanced localization and complex B2B setups. While Cart Transform works perfectly for standard products, the “black box” nature of Shopify Bundles pricing remains a challenge.

Are you struggling with VAT exemptions or complex B2B pricing on your Shopify store? At Newcraft, we specialize in navigating these platform limitations to build seamless commerce experiences.

Would you like us to audit your Shopify Plus setup or help you implement a workaround? Contact us today.