curl --request POST \
  --url {protocol}://{host}/wp-json/cocart/v2/cart/calculate \
  --header 'Content-Type: application/json' \
  --data '
{
  "return_totals": false
}
'

{
  "subtotal": "<string>",
  "subtotal_tax": "<string>",
  "shipping_total": "<string>",
  "shipping_tax": "<string>",
  "shipping_taxes": [
    123
  ],
  "discount_total": "<string>",
  "discount_tax": "<string>",
  "cart_contents_total": "<string>",
  "cart_contents_tax": "<string>",
  "cart_contents_taxes": [
    123
  ],
  "fee_total": "<string>",
  "fee_tax": "<string>",
  "fee_taxes": [
    123
  ],
  "total": "<string>",
  "total_tax": "<string>"
}