Pinterest has become a popular visual search engine and can be incredibly important to Shopify stores.
Pinterest themselves don’t have any documentation on JSON-LD but you can test your pages using their Rich Pins Validator (free account required) https://developers.pinterest.com/tools/url-debugger.
You’ll most likely need to click on the “Fetch New Scrape Information” button. Once you do this the first time, you shouldn’t need to do anything else. It just works.