# Testing Shipping Thresholds

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Setting up shipping threshold tests can be **very technical**, requiring thorough QA and monitoring to ensure tests are set up correctly. Therefore, we suggest working closely with a team of developers or upgrading to our [Pro plan](https://www.shoplift.ai/pricing) before launching a test on shipping thresholds.
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Testing different free shipping thresholds requires passing test assignment data through to checkout. Here's the recommended approach:

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#### Step 1: Create a JS API Test in Shoplift

Set up a new JS API test. This will generate two HypothesisIDs (one for each variant) that you will need to reference in your theme and checkout logic.
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#### Step 2: Expose HypothesisIDs as Cart Attributes

Store the assigned HypothesisID as a cart attribute. This ensures the visitor's test assignment persists through to checkout, where shipping rates are determined.
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#### Step 3: Create Shipping Methods in Shopify

Configure two separate shipping methods in Shopify, each corresponding to one of your test variants (e.g., free shipping at $50 vs. free shipping at $75).
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#### Step 4: Implement Assignment Logic

You have two options:

**Recommended: Shopify Function** Write a Shopify Function that reads the cart attribute and returns the corresponding shipping rate at checkout. This approach is cleaner and more stable for checkout-level control.

**Alternative: Theme Logic** Implement similar logic directly in the theme (can do this with JS API or theme tests). This works but offers less reliable control at the checkout stage.
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