Soft boost in merchandising works the same way as Soft Boost in Sort Orders, but is scoped to a specific merchandising rule instead of applying globally. This lets you boost products contextually — for example, boosting “sale” items only for visitors from a specific campaign.
How soft boost expressions work
When you create an expression in the merchandising rule builder, you can choose between two expression types:- Priority Rule (default): Pushes all matching products to the top of the sort order as a group.
- Soft Boost: Applies a decaying boost that naturally interleaves matching products throughout the results based on their existing sort performance.
Boost modes
Soft boost expressions support two modes: Multiplicative (default) amplifies products that already perform well on the base sort metric. The existing sort value is scaled by a decaying boost factor, so products with higher base values receive a proportionally smaller lift. Best for promoting products that are already performing and have non-zero metric values. Additive (percentile-based) lifts matching products in value space toward a target derived from the rest of the catalog, boosting them even when they have zero or near-zero base values. Best for sprinkling in products that may not have metric data yet — like new arrivals, recently restocked items, or products in a new category.Configuration parameters
Additive mode was rewritten on 2026-05-02 to lift products in value space (a percentile of the base metric) instead of by row position. Boost Strength is now used in additive mode to control how much of the gap to the target is closed. Existing additive merchandising rules continue to work, but you may need to retune Boost Strength and Percentile Target to match the new behavior.
When to use soft boost vs. priority rules
Soft boost expressions support the same targeting conditions as priority rule expressions. You can combine contextual conditions (geo, device, customer segment) with soft boosts for precise audience targeting.