You're right in that I don't need a rate API, but Shopify needs a shipping API. Something where I can say "6 shirt or 4 shirts and a jacket is flat rate, but 2

You're right in that I don't need a rate API, but Shopify needs a shipping API. Something where I can say "6 shirt or 4 shirts and a jacket is flat rate, but 2 shirts and a poster is not because of the tube"