Hi @Gb1996, 

Thanks for posting your question here. I love these custom integrations because you're able to built everything the way you want them to.

In regards to your question this should not be to difficult to do. There are a couple of ways you can go about it but I think the best way would be to have a date triggered flow but you could also do this using a segment triggered flow (just be aware a segment can take an hour to update and segment triggered flows only work once per subscriber) so my suggestion would be a date triggered flow.

In order for the date triggered flow to work you need to add a date to a customers profile property that contains the date. I would suggest also to use additional data you need in the email i.e. the place, or other specific information (doctor's name). 

You might want to look out for people who cancel their appointment, not sure how fast Klaviyo would change this date triggered flow if the date changes half way through, if they update this hourly then it might not be an issue otherwise you need to add a filter to remove people who cancelled their appointment.

Adding information to a profile can be done either through the webhooks in Klaviyo or you can code this on your end and send this to Klaviyo.

Some articles to help you:

• How to collect birthday
• Acceptable date formats
• How to create date property flow
• Segmenting on date property
• Date variables in emails

Omar Lovert // Polaris Growth // Klaviyo Master Platinum Partner

We help with e-commerce growth through CRO, Klaviyo and CVO