CART API can't generate shipping rates

[Nulls]

Hi All,

The cart API returns an empty JSON, no error message or anything. We are using https://community.shopify.com/c/shopify-design/cart-add-a-shipping-rates-calculator-to-your-cart/td-... , so it is pure javascript and liquid. It uses cart API as you know and Shopify needs to generate rates with a simple get request.

Here is the problem.

The customer adds a product (quantity x1)

https://www.billboardvinyls.com/products/10-x-36-new-white-vinyl-tarp?variant=39433160327251

When you check the shipping rates everything looks ok: https://www.billboardvinyls.com/cart/shipping_rates.json?shipping_address[zip]=35242&shipping_addres...

The customer changes the quantity x6 and Cart API can't generate rates anymore.

With the same quantity(x6) everything is fine at the checkout.

I believe this is a small bug but Shopify support redirects me here to get some help.

Any help would be much appreciated.

[Jason]

Are you doing this?

The recommended method to generate shipping rates is to use the POST /cart/prepare_shipping_rates.json and GET /cart/async_shipping_rates.json endpoints because it might take a while for shipping rates to be returned. The GET /cart/shipping_rates.json endpoint is subject to throttling

Without knowing what calls or frequency you're making them in perhaps you're seeing a throttle. See how it goes with the async options and if that yields better results first.

[Nulls]

Hi Jason,

Thank you for your time and answer but the tutorial uses post and async and it returns empty too for a certain weight.  If (an item x quantity) >= 150lbs then it returns empty. As I understood, cart API doesn't generate rates for LTL freights, or is there any way to force it?

[Nulls]

Anyone?