This is the documentation for Recommendations AI, Retail Search, and the new Retail console.

Model types

This page describes the recommendation models provided by the Retail API, with their default serving configurations and optimization objectives, available customizations, and supported event types.


When you sign up to use the Retail API, you work with Retail Support to determine the best recommendation models and customizations to use for your site. The models and customizations you use depend on your business needs, and where you plan to display the resulting recommendations.

When you request recommendations from the Retail API, you provide the serving configuration value to the placement resource. (See serving configurations for details about using the placement resource for serving configurations, and about support for placements, which were previously used by the Retail API to place models.) The serving configuration determines which model is used to return your recommendations. You can also filter your results.

Available recommendation types

The Retail API offers the following recommendation model types:

Others You May Like

The "Others You May Like" recommendation predicts the next product that a user is most likely to engage or convert with. The prediction is based on the shopping and viewing history of the user and the candidate product's relevance to a current specified product.

Default optimization objective: click-through rate

Default serving configuration: N/A

Available customizations:

Supported user event types:

Frequently Bought Together (shopping cart expansion)

The "Frequently Bought Together" recommendation predicts items frequently bought together for a specific product within the same shopping session. If a list of products is being viewed, then it predicts items frequently bought with that product list.

This recommendation is useful when the user has indicated an intent to purchase a particular product (or list of products) already, and you are looking to recommend complements (as opposed to substitutes). This recommendation is commonly displayed on the "add to cart" page, or on the "shopping cart" or "registry" pages (for shopping cart expansion).

Default optimization objective: revenue per order

Default serving configuration: N/A

Available customizations:

Supported user event types:

Recommended for You

The "Recommended for You" recommendation predicts the next product that a user is most likely to engage with or purchase, based on the shopping or viewing history of that user and contextual information of requests, such as timestamps. This recommendation is typically used on the home page.

"Recommended for You" can also be useful on category pages. A category page is similar to a home page, except that you display only items from that category. You can achieve this using a standard Recommended for You model with filter tags. For example, you can add customized filter tags (corresponding to each category page) to the items in your catalog. When you send the prediction request, set the user event object as category-page-view and specify a specific category page's tag in the filter field. Only recommendation results matching the requested filter tag are returned. Diversity should be disabled in this use case, because diversity can conflict with category-based filter tags.

Default optimization objective: click-through rate

Default serving configuration: N/A

Available customizations:

Supported user event types:

Similar Items

The "Similar Items" recommendation predicts other products that have mostly similar attributes to the product being considered. This recommendation is typically used on a product detail page, or when a recommended product is out of stock. It requires only information from the product catalog; no user events are required. Similar Items models cannot be tuned.

Default optimization objective: Click-through rate

Default serving configuration: N/A

Available customizations: N/A

Supported user event types:

Recently Viewed

The "Recently Viewed" recommendation is not actually a recommendation. It provides the IDs of products the user/visitor has recently interacted with, with the most recent products first.

Default optimization objective: N/A

Default serving configuration: recently_viewed_default

Available customizations: N/A

Supported user event types: All

Optimization objectives

Machine learning models are created to optimize for a particular objective, which determines how the model is built. Each model has a default optimization objective, but you can request a different optimization objective to support your business goals by contacting your support representative.

After you have trained a model, you cannot change the optimization objective. You must train a new model to use a different optimization objective.

The Retail API supports the following optimization objectives:

Click-through rate (CTR)

Optimizing for CTR emphasizes engagement; you should optimize for CTR when you want to maximize the likelihood that the user interacts with the recommendation.

CTR is the default optimization objective for the "Others You May Like" and "Recommended for You" recommendation model types.

Revenue per order

The revenue per order optimization objective is the default optimization objective for the "Frequently Bought Together" recommendation model type. This optimization objective cannot be specified for any other recommendation model type.

Conversion rate (CVR)

Optimizing for conversion rate maximizes the likelihood that the user adds the recommended item to their cart; if you want to increase the number of items added to a cart per session, optimize for conversion rate.

Advanced model configuration options

Depending on the model type, there are some other model configuration options you can use to change the behavior of your model.

Tuning preference

Tuning keeps model training optimal as input data changes over time. Set your model to automatically tune every three months, or choose to only tune it manually. The model automatically tunes one time after creation. Learn more.

For tuning cost details, see Pricing.

Available serving configurations and models

Before you can request predictions from your model, you must create at least one serving configuration for it. For more information, see Create serving configurations.

You can see your models listed on the Models page. Click a model name to go to its details page, where you can see serving configurations associated with that model.