Cal.com API Sandbox
Scheduling products combine booking flows, availability, auth, and follow-up updates. Those flows get annoying fast when you are trying to test them across a pile of partial mocks.
Why scheduling APIs get annoying fast
Booking APIs look simple in the first five minutes. Then you need to test availability, booking state, follow-up actions, and whatever your app does after the booking changes. That is where static mocks stop feeling very comforting.
Start with narrow flows
The best proof points in the onboarded Cal.com spec are not "282 endpoints." They are two narrow workflows you can actually trust: one for reservation before confirmation, and one for the full booking lifecycle after the booking exists.
Reserve a slot, then confirm it
Test the timing-sensitive path where a slot is available, gets held temporarily, and must become a real booking before the reservation expires.
Create, reschedule, then cancel
Test the booking state transitions after creation so fetch, reschedule, cancel, and follow-up events stay connected to the same booking.
Why this page exists
Scheduling APIs are a pretty good example of why I built this product in the first place. A team wants to prove the booking flow works, not admire one example response and pretend that means the integration is fine.