Advanced engine for recommendations

The advanced engine lets you combine multiple recommendation models into a single customized setup. Instead of using one model on its own, you can mix different models, set priorities, and choose how results are combined—giving you more control over what gets recommended and when.

Available engines

You can combine any of the following engines:

NameTemplate
Manual selectionManual selection technique
New itemsNew items
Chosen by metricChosen by metric
More like thisMore like this
Textual similarityText model
Customer recent interactionsCustomer recent interactions
Personalized recommendations for youPersonalized recommendations for you

The Personalized recommendations for you model lets you add as many events as you want, each with its own weight. Weight is a positive number that represents how strongly an event signals user preference. The higher the number, the stronger the signal.

Understanding the weight parameter

Weight controls how much each user action influences recommendations. To use it well, it helps to understand the difference between explicit and implicit feedback.

How weight works with implicit feedback

Explicit feedback is when a user directly rates something. For example, giving a film 1 to 5 stars. The rating itself is the signal.

Implicit feedback uses actions like view_item, add_to_cart, and purchase events. These don't tell you whether a user liked something—only that they interacted with it.

In implicit feedback models, the system infers preference and assigns a confidence level to that inference. Weight directly affects that confidence level. An event with weight: 3makes the model three times more confident that a user likes an item compared to an event with weight: 1.

Recommended weight settings

EventSuggested weightRationale
view_item1Lowest intent — just browsing. Gives a broad but weak signal.
add_to_cart5Much stronger than a view. The user shows clear intent to buy.
purchase10–20The strongest signal. The user has bought the item and shown real preference.

Set up the advanced engine

Choose a catalog

Select a product catalog containing all your products. Apply a catalog filter to limit results to relevant items — most commonly used to show only in-stock products.

Product catalog filter settings for recommendation engine in Bloomreach Engagement

Catalog selection and filter settings.

Add and configure models

Under Choose and set up the recommendation models, click + Add engine to add a model from the list. You can add multiple models and assign each one a priority number.

Add engine button and model selection menu in Bloomreach Engagement

Adding an engine and selecting a model.

This example uses 2 models: More like this and Personalized recommendations for you. They have priorities 1 and 2.

The system shows all results from the More like this model first (priority 1), followed by results from the Personalized recommendations for you model (priority 2).

Example setup of More like this and Personalized recommendations for you models with priorities

Example of Advanced template with 2 models

Select the combination strategy

Once you've added your engines, choose how to combine their results:

Combination nameWhat does it mean
Only the best oneThe system picks the best-performing model after it receives at least 1,000 views (recommendations.action = view) across all engines. The model with the most clicks (recommendations.action = click) wins.
Combine multipleResults from all engines are mixed together.
Order by priority of models
(You can set priorities in the previous step while designing engines)
Engines are used in priority order. The system starts with priority 1 and moves to the next only if there aren't enough results. Useful for setting up fallback models when personalization isn't possible.
Dropdown menu for selecting recommendation combination strategy in Bloomreach Engagement

Combination strategy options.

Model combinations

Mixing engines is especially useful for email recommendations, where you want the most relevant results possible. A good pattern is to use a manual selection engine at the lowest priority as a fallback. It kicks in only when other engines don't return enough results.

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Note

Adding more models increases API response time.