Query available booking slots for a Cal.com event type within a date range and timezone using the Cal.com API v2 GET /v2/slots endpoint.

Documented steps

1. Set Authorization: 'Bearer <API_KEY_OR_ACCESS_TOKEN>' if the event type is private/hidden; public event types can be queried without auth, but unauthenticated calls are rate-limited.
2. Set header cal-api-version: 2024-09-04 on every request to this endpoint; omitting it makes the API fall back to an older, differently-shaped response.
3. Send GET https://api.cal.com/v2/slots with one identifier combination: eventTypeId=<number>, OR eventTypeSlug + username (individual), OR eventTypeSlug + teamSlug (team event), OR usernames=<comma-separated, min 2> for dynamic events.
4. Include required query params start=<UTC ISO 8601 date or datetime, e.g. 2050-09-05 or 2050-09-05T09:00:00Z> and end=<UTC ISO 8601> to bound the search window.
5. Optionally add timeZone=<IANA tz, e.g. America/New_York> to convert slots to that zone; if omitted, results are UTC.
6. Optionally add duration=<minutes> to override the event type's default length when the event type supports multiple durations.
7. Optionally add format=range to receive {start,end} objects per slot instead of the default array of start-time strings (format=time).
8. Optionally add organizationSlug for org context, and bookingUidToReschedule=<uid> to exclude an existing booking's busy time when finding reschedule slots.
9. Parse the response: {status:'success', data:{...}} where data is keyed by date string (YYYY-MM-DD), each value an array of slot times (or {start,end} objects with format=range).
10. Treat an empty data object {} as 'no slots available in this range' rather than an error; check the status field before assuming failure.
11. Docs: https://cal.com/docs/api-reference/v2/slots/get-available-time-slots-for-an-event-type