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Francisco
04/10/2026, 7:20 PM@AI Evy @Omar Ashraf | Community Lead Hi! I'm using the built-in check_availability_cal
function with Cal.com v2 API. Cal.com support confirmed
that the slots API needs a timeZone parameter
(e.g. timeZone=America/Los_Angeles) to return correct
availability.
Is the check_availability_cal function passing a
timeZone parameter to the Cal.com v2 slots API?
If not, is there a way to configure this?
Event Type ID: 5229338
Timezone: America/Los_Angeles
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AI Evy
04/10/2026, 7:21 PMThanks for tagging me @Francisco. I'll look through relevant sources and get back to you shortly.
AI Evy
04/10/2026, 7:21 PM### Answer
Yes, the check_calendar_availability function does support timezone configuration [(1) ]() . When you add a check calendar availability function in Retell, you can optionally add a timezone to be used in the function .
To configure this:
1. Navigate to the agent's Functions section
2. Add or edit your check calendar availability function
3. Enter your API Key from Cal.com and Event Type ID
4. In the optional timezone field, specify your timezone (e.g., "America/Los_Angeles")
The timezone parameter you configure will be passed to the Cal.com API when checking availability .
There was a previous bug related to timezone handling where AM/PM indicators weren't being correctly interpreted, but this has been fixed [(2) ]() .
AI Evy
04/10/2026, 7:21 PM
To learn more, see the sources I considered:
[[1] Check Calendar Availability](https://docs.retellai.com/build/check-availability)
[[2] When using check_calendar_availability function, I am getting all the times in AM (same timezone)](https://discord.com/channels/1186424376300679209/1291338582388248637)
AI Evy
04/10/2026, 7:21 PMFeel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.