Add support for custom variables in customer records for personalised review requests

It would be very helpful to have the ability to store custom variables/fields for each customer when creating or importing records. These variables could then be used in review request emails to make them more personal.

Example:
When importing a customer, we could include a field such as “product,” “service,” or “item” and use it in the email template:

Thank you for your recent booking. We hope you enjoyed the {{service}}!

Benefits:

• More personalised and relevant emails

• Higher engagement and review completion rates

• Flexibility to include context such as product type, service booked, or team member’s name

How it could work:

• Allow custom key/value fields when creating or updating a customer via import or API

• Make these variables available as merge tags in email templates (e.g., {{custom.service}})

This would help businesses across different industries create messages that feel tailored rather than generic.