Does SubsiMail integrate with Calendly for booked meetings?

Not a native one, but this is a pretty common Zapier setup: trigger on Calendly's “Invitee Created” event, then use SubsiMail's “Add Tag to Contact” or “Move Contact to List” action to mark them as booked (matching by email address). That lets you exclude booked contacts from further follow-up sequences automatically, which is usually the actual goal.