Personalization rules are business logics that you can apply on top of your product recommendations. Personalization rules enable you to tailor the recommended product set to your business needs. You can create a personalization rule by using a base logic. A base logic is nothing more than a product recommendation logic that returns a selection of products based on a pre-defined calculation. Once a base logic has been selected, you can add business-specific criteria that filters your product catalog based on your use case, for example filtering based on price range or including/excluding certain brands or categories.

To check the existing rules, navigate to Content > Personalization Rules.

The requirements for using Personalization rules are the following:

• Existing, up-to-date product catalog
• All standard Web Extend commands implemented
• Personalization rules work only for contacts who have received a campaign (any email communication) in the last 180 days
• Before starting the calculation of a personalization rule, you have to send an email to the target of your campaign. This is needed for the correct synchronization of the contact data before the calculation.  
• Block-based email campaign including at least one repeatable block with editable fields: Link, Image, Title, CTA to display a product and it is also repeatable.

All the existing Personalization rules that have been created earlier in your account are listed on the Personalization rules page.

For more information, see Defining a Personalization rule.

• Personalization rules do not work with on-event, triggered or transactional email campaigns in Automation Center or Interactons programs. Personalization rules only work with recurring and batch email campaigns.
• Campaign scheduling and frequency of specific Personalization rules impact the reliability of Personalization rules being displayed or may result in delayed email sends.
• Personalization rules limitation - The maximum number of Personalization rules per campaign: 5.
• You can use custom fields in Personalization rules but only strings are supported.
• You can use a maximum number of 20 different fields per campaign. If you use the same field in different Personalization rules, it only counts as 1.
• You cannot use localized fields within the rule builder when creating a Personalization rule.
• If a campaign using Personalization rules is sent before calculation has finished for that rule, it will not be delivered and the "no content" error message will be displayed.
• If so many filtering criteria are applied that no products can be returned, then the campaign will not be sent.