Just before the order payment is being done, we crawl the URL of the product, we check for a product with the specified ID and validate that the price, name, any other properties have not been altered. If it has been altered, we reject the order. The URL in data-item-url must be on your site domain, so by example, if you change the data-item-url from snipcart.com/product to myapp.com/product, it will be considered as altered and the order will be rejected.