First-match-wins evaluation
When multiple rules target the same collection/sort combination, the system evaluates them in database order (typically by creation date). The first rule whose contextual conditions match the current session context is applied. Rules without contextual conditions always match and act as fallback rules. Example scenario:Rules are evaluated in the order they were created. If you need to change rule precedence, you may need to recreate rules in the desired order.
Overlap detection validation
To prevent conflicting merchandising rules, the system validates that contextual conditions don’t overlap when creating or updating rules. This ensures that only one rule can match a given visitor at any time. What constitutes overlapping conditions: The system analyzes the contextual conditions of all existing rules for the same collection/sort combination and determines if the new rule’s conditions could match the same visitor as an existing rule. Non-overlapping conditions (allowed):country == USandcountry == CA(different equality values)country in [US, CA]andcountry in [UK, DE](no common values)source == klaviyoandsource == google(different marketing sources)
country == USandcountry == US(identical conditions)country in [US, CA]andcountry in [CA, UK](common value: CA)country == USandcountry in [US, CA](US is in the list)
The overlap detection uses heuristic analysis and may not catch all complex overlapping scenarios with deeply nested OR conditions. The validation provides best-effort protection while allowing legitimate non-overlapping rules to coexist.