I’m about to build a Shopify Plus extension that applies shipping fees based on the customer’s delivery postcode. My client has provided a complete list of postcode-to-shipping-rate mappings. Which type of Checkout UI extension or API would allow me to adjust the shipping fee dynamically at checkout?
I’ve also seen paid third-party apps offering similar functionality. I assumed that we can develop whataver function that provided by third party app but I haven’t found any exposed API endpoints that fit my requirements.
Please advice. Thanks!