Inconsistent `total_price` Across Cart APIs When Logged In as a Customer

[haddi]

Hey everyone,

I’m encountering an issue where the total_price is calculated inconsistently across different cart APIs, and it’s leading to discrepancies in the cart totals. This only happens when logged in as a customer, which seems to trigger Shopify to include the shipping cost based on the address.

Here’s the situation:

• Product price: $3,050
• Flat rate shipping: $299

When logged in as a customer, Shopify starts including the shipping cost in the total_price, but only inconsistently across different APIs. Here’s what I’ve found:

1. /cart.js and Liquid’s cart object:

• total_price: 305000
• original_total_price: 305000

2. /cart/update.js’ response after updating the cart with it:

• total_price: 334900
• original_total_price: 305000 (Shipping cost $299 is added to total_price, but original_total_price remains unchanged.)

3. /cart/change.js’ response after updating the cart with it:

• total_price: 334900
• original_total_price: 305000 (Shipping cost $299 is added to total_price, but original_total_price remains unchanged.)

Is there any explanation for why the shipping cost is included in the object returned by /cart/update.js and /cart/change.js but not in the /cart.js or Liquid’s cart object? I couldn’t find anything in the documentation that addresses this behavior.

Appreciate any insights!

[Daniel_Victor_map]

Shopify includes shipping costs in /cart/update.js and /cart/change.js only after customer login, due to address-based shipping estimation. /cart.js and Liquid objects don’t auto-trigger shipping calculation. To ensure consistency, explicitly calculate shipping using shipping_address in backend logic or rely on /cart.js before checkout. Avoid comparing APIs unless shipping estimation logic is uniform across them