What is being booked?
A clinician, room, lesson, or repair slot has different rules. Define duration, staff member, location, capacity, gaps, rescheduling, and waitlists. These rules are the core system, not interface details.
Prevent double bookings
Define when a slot is held, what happens if two users select it, and who can override availability. Staff need an operable calendar, not only a request list. Test time zones if bookings cross borders.
- Cancellation, lateness, and no-show rules.
- Customer, staff, and manager permissions.
- Reminder channels actually available in the target market.
Cost drivers
Deposits, branches, multiple providers, subscriptions, external calendars, notifications, and reporting all add work. Price each integration separately from the core booking engine and clarify its recurring fees and account owner.
A testable first release
Start with one service type, a small team calendar, and clear cancellation rules. Operate bookings before adding a multi-provider marketplace or dynamic pricing. Measure conflicts, cancellations, and rescheduling friction rather than screen count.