We are building a real-time shipping rate app for people who operate a web store on Square. I noticed Square already has a help article (Set Up Real Time Shipping with Square Online | Square Support Center - US) for merchants who want to set up custom carrier and real-time shipping rate calculation for common carriers like USPS, DHL etc. It briefly addresses custom carrier + flat rate, but does not provide a way for shipping rates to be dynamically calculated. I had a look at developer API and didn’t find relevant APIs specifically for shipping.
Would appreciate help from people who can point us to the right direciton.
We briefly spoke on Slack, but to reiterate: unfortunately, we don’t have any services/APIs that will calculate shipping rates for you. Within an Order object, you can supply a fulfillments array, and make it of type SHIPPING. Within this model, you can add a carrier string, tracking_number/url and similar things. All of these would need to be manually set by the developer application, though.