I’m adding a line item for the shipping total, and am unable to set the tax as $0 using setTotalTaxMoney on the item (fails with ‘Read-only field is calculated and cannot be set by a client.’), maybe because the entire order’s tax is auto calculated.
Is there another way to add a shipping amount without having that be included in the tax calculation? Or should I not use setAutoApplyTaxes, and instead apply taxes to each item individually?
Is the shipping amount an actual item in your Catalog or is this an adhoc item? If it’s a variable priced item from the catalog you can configure the item to not include taxes. Otherwise you can add pricing_blocklists with a list of the IDs you want to block from applying to the item. 
Thanks for the quick response! The shipping item is created with the API during checkout (so adhoc?), not an existing item created from the user dashboard.
I saw the option in the account settings to disable tax on custom amounts but it requires i add a Dining Option
Would it be easier to create an item in the dashboard and add it to the exempt list there? I don’t know what the tax id would be if I used the OrderLineItemPricingBlocklistsBlockedTax list.
You can definitely do either. If you need to get a list of all the tax_ids you can call ListCatalog and set the type to TAX so it will give you a list of taxes associated to your catalog.
Thanks, I got the Tax ID and was able to use the blocklist through the API.
That’s fantastic!!! 
Thanks. This is what i’m searching.
