ShipStation deployed the Checkout Rates feature early in 2021 (previously called In-Cart Delivery Options). It currently works for Shopify, Magento, Wix, and BigCommerce store integrations. But there are more store integrations planned!
You can learn about the feature in our Send Rates to Store Checkout help article.
We will leave this idea in the Started status until we have a few more stores added to the feature.