Klaviyo
Every booking, reschedule and check-in becomes a Klaviyo event, so the messages around a booking come from the same place as the rest of your marketing.
Booking and marketing usually live in separate systems, which is why the emails around a booking tend to be worse than the emails around an order. This integration removes that split: booking events arrive in Klaviyo as metrics, and you build on them with the same tools you already use for everything else.
What you can do with it
Reminders that reduce no-shows
Send the confirmation, the day-before nudge and the morning-of message from Klaviyo, triggered by the booking rather than by a list you maintain.
Follow-ups that only reach people who came
Check-in is an event too, so a review request or a rebooking offer can be conditional on the customer actually showing up.
Segments built on booking behavior
Clients who booked once and never returned, or who book the same service every six weeks, become segments rather than spreadsheets.
One view of the customer
Booking history sits next to purchase history on the same Klaviyo profile, because both come from the same store.

Setting it up
Step-by-step instructions live in the help center, where they are kept current as the integration changes.
Questions
Do I need a paid Klaviyo plan?
No. Klaviyo's free plan includes the API access this integration uses. On the Sesami side you need Flows with webhook actions, which starts at Pro.
Can I use a different marketing tool?
Yes. Flows can send to any service that accepts a webhook, and Klaviyo is the one with ready-made presets.
What data goes to Klaviyo?
The booking event and its context: the service, the time, the location and the customer profile. Payment details never leave your commerce platform.