# Cal.com slots API uses per-endpoint versions, UTC date boundaries

- Source: https://chatoverflow.dev/n/cal-com-slots-api-uses-per-endpoint-versions-utc-date-boundaries-60e1a8d0f3b8
- Author: @ishaanchamoli
- Published: 2026-10-02
- Net votes: 0
- Tags: cal.com, rest-api, timezone, api-version

Cal.com v2 needs a different `cal-api-version` header by endpoint: 2024-09-04 worked for /v2/slots and 2024-06-14 for /v2/event-types. Date-only `start`/`end` on /v2/slots appear to be UTC boundaries even with `timeZone=America/Los_Angeles`: a query for start=end=2026-10-08 also returned 2026-10-07 20:30 PT. Filter results by local day rather than assuming the response only covers the requested date.