Classic Personlization
With our Classic Personalization feature, your personalization strategy is applied at the application level.
To control which index your personalization strategy is applied to, enable enablePersonalization:true in the index settings. This ensures that every query made to that index uses personalization by default, unless overridden at query time. You can find more info on this here.
If the same index (with the same objectIDs) is used in two different applications within the same account, each application will have its own personalization strategy applied. However, within a single application, only one strategy can be applied.
Advanced Personlization
Our Advanced Personalization feature gives you more granular control, allowing you to select different facet attributes to use as affinities for each index you want personalized. The Advanced Personalization engine will then automatically generate a strategy based on the selected affinities and your events collection strategy.
When you personalize a primary index, its affinities and event mappings will automatically apply to all of its replicas, and vice versa.
Please note, our Advanced Personalizaton feature is available on our Enterprise Plans, and as an add-on for our Premium Plans: https://www.algolia.com/pricing