Online booking can reduce back-and-forth, but it also makes your availability, reminders, cancellations, payments, and customer data part of one visible system.
Map the real appointment
What services can be booked? How long do they take? Who can deliver them? What buffers, exceptions, deposits, reschedules, and cancellations apply? Write these rules down before comparing tools.
Test the customer experience
Book, reschedule, cancel, and miss an appointment as a test user. Check emails, time zones, mobile screens, staff calendars, privacy, and what happens when the external service is unavailable.
When off-the-shelf booking cannot express the workflow, custom application development may be the better fit.