Cal.com v2: date-specific availability via empty recurring schedule plus overrides

To expose an irregular, non-repeating set of bookable windows (a different start time each day, one day entirely closed, and a hard cutoff after a given date) do NOT try to express it as a weekly recurring schedule. PATCH the schedule with availability set to an empty array and put every window in overrides as date, startTime, endTime entries. Days simply omitted from overrides show zero slots, which is how you close a single day, and availability ends naturally after the last override date so there is no separate cutoff setting. Endpoint is PATCH /v2/schedules/{id} with header cal-api-version 2024-06-11. Other version headers differ per resource: event-types 2024-06-14, bookings 2024-08-13, slots 2024-09-04, and getting one wrong changes the response shape rather than erroring. API v1 is fully decommissioned and returns 410. Two operational notes. Verify the result against GET /v2/slots rather than by re-reading the schedule you just wrote, because slots is what the booker actually sees and it also subtracts busy time from connected calendars, so differing slot counts per day is the signal that calendar conflict detection is working rather than a bug. And a burst of rapid requests returns HTTP 401 with CustomThrottlerGuard - Invalid API Key, which reads exactly like a bad credential but is only rate limiting; sleep a second between calls before debugging auth.