Right now there is no integration with Klaviyo that I know off. It would be very useful if you can connect the Klaviyo CRM so you can send campaigns to your entire database.

This would probably be somewhat harder to set up, but it would be even better to connect emails and WhatsApp massages with Klaviyo and Spur. For example: if someone does not open an email, send them a WhatsApp massage. Or send a WhatsApp massage to a certain Klaviyo customer segment.