Can I show a calendar first and let visitors filter services?

Yes. Both packages expose getFlowAvailability(bookingConfigId, options). It returns the services bookable on each date, with optional time slots. Your application supplies the calendar, filter controls, and service-card layout.

Use dateFrom and dateTo for up to seven venue-local dates per request. Pass partySize and, where supported by the service, lengthMinutes. After a visitor chooses a day, request that single date with includeSlots: true for exact times. Re-fetch when the party size or customer session changes.

Use catalog categories, tags, and service fields for additional filtering in your own code. The Hosted Package's basic service-card attributes render a collection; they do not supply a finished visitor filter interface. You can choose the Customer Flow in advance and add interactive filters with JavaScript.

When partial is true, show that availability is incomplete and retry; a failed lookup does not mean the service is sold out. See DOM calendar-first browsing and Hosted calendar-first browsing.