Nosto also supports multiple optional values which may enrich the usage of the service, but are not required. These span elements should be inserted into the "nosto_product" parent container.
Prices must always be denoted in a simple numerical form using dot as the decimal separator. For example, 1.234,45 is invalid while 1234.45 is valid.
Tagging the categories
Categories must always be delimited by a slash. For example, /Home/Accessories is a valid category while Home > Accessories is not.
Tagging the currencies
Currencies should always be represented in the ISO-4471 three-letter format. For example, use the code USD instead of $ to represent the United States Dollar.
Tagging the availability
The availability of a product is represented by InStock or http://schema.org/InStock for products that are in stock and saleable. For products that are out of stock or you don't want to be recommended, you can use OutOfStock or http://schema.org/OutOfStock
The rating of a product must be represented as a number between 0.0 and 5.0. For example, a product cannot be rated 9.1. You must normalize your rating value to fit our specified range.
Tagging the Tags and/or Custom fields
The three tag fields, tags1, tags2 and tags3 are simply labels that can be used to annotate tags like discounted, limited collection or other use cases where you might want to filter your Nosto recommendations by certain product groupings.
Custom fields accept a key:value pair where the class of the attribute is the key. Common use cases are material, color or other similar unique identifiers.
Fields that are not exposable in tagging
Nosto also supports two attributes that are not crawlable through tagging. This is due to the sensitive nature of the attributes. They are: supplier_cost and inventory level. To send these two values to Nosto you will need to use the Products API.
Adding support for advanced use cases
Many e-commerce stores utilize SKU:s or "child" products that are sorted under the same "parent" product. To extend the above example with SKU support refer to this article​
In cases where a product might have multiple prices in differing currencies, you can also add support for multi-currency. Refer to this article​
Supplier Cost / Margin Filter
If you want to use Nosto’s margin filter, you need to send supplier cost via API since it's a sensitive data that you might not want to expose in the product tagging.
Troubleshooting
Once included on all pages, you can review if the site is transmitting data using the Nosto Debug Toolbar. If you can see product attributes being picked up under "Tagging" then the product details are correctly set up. You can further verify that products are being indexed to the catalog under the Nosto admin by navigating to Tools → Products: https://my.nosto.com/admin/$accountID/campaigns/products/list​