Google Calendar Not Booking Events + Wrong Time Detected

dual-salmon · 2025-10-28T06:12:05.720Z

Hi Vapi Team, I’m having an issue with my Google Calendar integration in my Zapi/Vapi voice assistant. What’s happening: When users book a viewing (e.g. “October 27 at 10 AM”), the assistant interprets the wrong date/time (like “October 6”). It says the event was booked, but nothing appears on my Google Calendar. My custom email tool still works fine — only the calendar part fails. Setup details: Using google_calendar_check_availability_tool (8 AM–7 PM, 45-min slots) Using google_calendar_tool to confirm and create 45-min events with user info Google account is connected and active Timezone: Europe/Lisbon Possible causes: Timezone mismatch Event data (start_time / end_time) not being passed correctly Could you please check if there’s an issue with Google Calendar integration or confirm the correct setup for timezone handling? I can share screenshots of my tool configs if needed.

V

Vapi Support BotAPP•10/28/25, 6:13 AM

Thank you for the details. To help pinpoint the issue, could you confirm whether your Google Calendar tool configuration explicitly sets the

timeZone

timeZone

timeZone

timeZone field to "Europe/Lisbon" and that your

startDateTime

startDateTime

startDateTime

startDateTime/

endDateTime

endDateTime

endDateTime

endDateTime values are in ISO 8601 format? This will help rule out timezone or formatting mismatches as the cause.

If you can, please share a snippet of your tool’s configuration for these fields (no need for full screenshots yet).

Source:

Google Calendar Tool Documentation

⤵️ Mention @Vapi Support Bot for follow-ups 🐥

D

dual-salmonOP•10/28/25, 6:24 AM

@Vapi Support Bot here is the snippet of my tools config for these fields, please tell me why it isn’t working

V

Vapi Support BotAPP•10/28/25, 6:25 AM

Thank you for confirming the

timeZone

timeZone

timeZone

timeZone setting. To help pinpoint the issue, could you please share the exact values you are passing for

startDateTime

startDateTime

startDateTime

startDateTime and

endDateTime

endDateTime

endDateTime

endDateTime in your event creation payload? This will help verify if they are in the required ISO 8601 format and match the intended date/time.

If possible, just copy and paste those two values here (no need for a full config). This will help us check for any formatting or timezone issues.

Source:

Google Calendar Tool Documentation

D

dual-salmonOP•10/28/25, 6:33 AM

@Vapi Support Bot here is what appears when I book a schedule (summary": "Property Viewing with John",
"attendees": ["john@gmail.com"],
"timeZone": "Europe/Lisbon",
"startDateTime": "2023-10-29T17:45:00",
"endDateTime": "2023-10-29T18:30:00",
"description": "Client's phone number: 12345678")

D

dual-salmonOP•10/28/25, 6:34 AM

@Vapi Support Bot

V

Vapi Support BotAPP•10/28/25, 6:35 AM

It looks like your

startDateTime

startDateTime

startDateTime

startDateTime and

endDateTime

endDateTime

endDateTime

endDateTime are set to 2023, which is likely why nothing appears on your calendar for the intended date. Make sure your assistant generates the current year dynamically when parsing user input. For example:

"startDateTime": "2025-10-27T10:00:00",
"endDateTime": "2025-10-27T10:45:00",
"timeZone": "Europe/Lisbon"

"startDateTime": "2025-10-27T10:00:00",
"endDateTime": "2025-10-27T10:45:00",
"timeZone": "Europe/Lisbon"

"startDateTime": "2025-10-27T10:00:00",
"endDateTime": "2025-10-27T10:45:00",
"timeZone": "Europe/Lisbon"

"startDateTime": "2025-10-27T10:00:00",
"endDateTime": "2025-10-27T10:45:00",
"timeZone": "Europe/Lisbon"

Double-check your date parsing logic to ensure the year matches the user's intent and is in the correct ISO 8601 format with the right timezone. According to the documentation, incorrect or past dates will prevent event creation (Google Calendar Integration).

Source:

Google Calendar Integration

V

Vapi Support BotAPP•10/28/25, 6:35 AM

Your
startDateTime
startDateTime
startDateTime
startDateTime and
endDateTime
endDateTime
endDateTime
endDateTime values are missing the required timezone offset in ISO 8601 format. Update them to include the offset for Europe/Lisbon (e.g.,

+01:00

+01:00

+01:00

+01:00 or

+00:00

+00:00

+00:00

+00:00 depending on DST):

"startDateTime": "2023-10-29T17:45:00+01:00",
"endDateTime": "2023-10-29T18:30:00+01:00"

"startDateTime": "2023-10-29T17:45:00+01:00",
"endDateTime": "2023-10-29T18:30:00+01:00"

"startDateTime": "2023-10-29T17:45:00+01:00",
"endDateTime": "2023-10-29T18:30:00+01:00"

"startDateTime": "2023-10-29T17:45:00+01:00",
"endDateTime": "2023-10-29T18:30:00+01:00"

This should resolve both the wrong time interpretation and the event not appearing in Google Calendar.
Reference: Google Calendar Tool Documentation

Source:

Google Calendar Tool Documentation

D

dual-salmonOP•10/28/25, 6:42 AM

@Vapi Support Bot where do I change the date

V

Vapi Support BotAPP•10/28/25, 6:44 AM

To change the date, go to your Vapi Dashboard, open your assistant, and edit the Google Calendar event creation tool. Update the logic or field that sets

startDateTime

startDateTime

startDateTime

startDateTime and

endDateTime

endDateTime

endDateTime

endDateTime so it generates the correct year and includes the timezone offset. For example:

"startDateTime": "2025-10-27T10:00:00+01:00",
"endDateTime": "2025-10-27T10:45:00+01:00"

"startDateTime": "2025-10-27T10:00:00+01:00",
"endDateTime": "2025-10-27T10:45:00+01:00"

"startDateTime": "2025-10-27T10:00:00+01:00",
"endDateTime": "2025-10-27T10:45:00+01:00"

"startDateTime": "2025-10-27T10:00:00+01:00",
"endDateTime": "2025-10-27T10:45:00+01:00"

Make sure these fields are set dynamically based on the user's request and current year in your tool configuration (Google Calendar Tool Documentation).

Source:

Google Calendar Tool Documentation

D

dual-salmonOP•10/28/25, 3:27 PM

@Duckie I don’t have those options

V

Vapi Support BotAPP•10/28/25, 3:29 PM

Thank you for clarifying. To help you further, could you please specify whether you are editing an Assistant or a Workflow in the Vapi Dashboard, and describe what options you do see under the "Tools" or event creation section? This will help me guide you to the correct place to update your

startDateTime

startDateTime

startDateTime

startDateTime and

endDateTime

endDateTime

endDateTime

endDateTime fields.

If possible, a brief description or screenshot of your current screen would be helpful (please omit any sensitive information).

Source:

Google Calendar Tool Documentation

D

dual-salmonOP•10/28/25, 3:30 PM

@Duckie I have tool name, description, calendar settings, calendar id, time zone, messages

V

Vapi Support BotAPP•10/28/25, 3:32 PM

Thank you for the details. In the "messages" section of your tool configuration, do you see any fields or templates where variables like

startDateTime

startDateTime

startDateTime

startDateTime or

endDateTime

endDateTime

endDateTime

endDateTime can be inserted or referenced? If so, could you briefly describe what options or fields are available there?

Source:

Google Calendar Tool Documentation

D

dual-salmonOP•10/28/25, 3:34 PM

@Duckie this is what I have

V

Vapi Support BotAPP•10/28/25, 3:36 PM

The "Messages" section only controls what is spoken to the user—it does not set the event's date or time.
To fix your issue, you need to update the logic or variables that populate the

startDateTime

startDateTime

startDateTime

startDateTime and

endDateTime

endDateTime

endDateTime

endDateTime fields in your Google Calendar tool configuration (not in the "Messages" section). For example:

"startDateTime": "2025-10-27T10:00:00+01:00",
"endDateTime": "2025-10-27T10:45:00+01:00"

"startDateTime": "2025-10-27T10:00:00+01:00",
"endDateTime": "2025-10-27T10:45:00+01:00"

"startDateTime": "2025-10-27T10:00:00+01:00",
"endDateTime": "2025-10-27T10:45:00+01:00"

"startDateTime": "2025-10-27T10:00:00+01:00",
"endDateTime": "2025-10-27T10:45:00+01:00"

Make sure these fields are set dynamically based on user input and include the correct year and timezone offset.
Reference: Google Calendar Tool Documentation

Source:

Google Calendar Tool Documentation

D

dual-salmonOP•10/28/25, 3:54 PM

@Duckie yes but I don’t have that option

V

Vapi Support BotAPP•10/28/25, 3:56 PM

Thank you for confirming that you don't see options to set

startDateTime

startDateTime

startDateTime

startDateTime or

endDateTime

endDateTime

endDateTime

endDateTime. Are you editing a pre-built tool, a custom tool, or a workflow node in the Vapi Dashboard? Knowing this will help determine if there’s a UI limitation or if a different configuration path is needed.

If possible, please specify the exact type of tool or workflow you are editing (e.g., "Assistant > Tools" or "Workflow > Node"), so I can guide you to the correct place or suggest next steps.

Source:

Google Calendar Tool Documentation

D

dual-salmonOP•10/28/25, 5:51 PM

@Vapi Support Bot I’m using a pre built tool that is google calendar search for events and book events google calendar and I’m using assistant > tools

V

Vapi Support BotAPP•10/28/25, 5:53 PM

Thank you for clarifying that you're using the pre-built Google Calendar tool under "Assistant > Tools." To help determine the next steps, could you confirm if you see any "Advanced" or "Variables" section in the tool configuration, or is your access limited strictly to the basic fields (name, description, calendar settings, calendar id, time zone, messages) with no way to map or edit event details like

startDateTime

startDateTime

startDateTime

startDateTime and

endDateTime

endDateTime

endDateTime

endDateTime?

This will help identify if the UI is limiting your ability to set these required fields, or if a custom tool/workflow is needed for your use case.

Source:

Google Calendar Tool Documentation

D

dual-salmonOP•10/28/25, 5:55 PM

@Vapi Support Bot my access is limited to the basic fields

V

Vapi Support BotAPP•10/28/25, 5:56 PM

Thank you for confirming your access is limited to basic fields. Are you able to create or switch to a custom tool or workflow in your Vapi Dashboard? This may be necessary to set the required

startDateTime

startDateTime

startDateTime

startDateTime and

endDateTime

endDateTime

endDateTime

endDateTime fields for Google Calendar event creation, as the pre-built tool does not expose these options (Google Calendar Tool Documentation).

Source:

Google Calendar Tool Documentation

D

dual-salmonOP•10/28/25, 6:00 PM

@Vapi Support Bot yes I can create a custom tool but how can I make it into google calendar

V

Vapi Support BotAPP•10/28/25, 6:02 PM

To create a custom Google Calendar tool that lets you set

startDateTime

startDateTime

startDateTime

startDateTime and

endDateTime

endDateTime

endDateTime

endDateTime, go to Dashboard > Tools > Create Tool, select Google Calendar, and fill in the required fields. For example:

{
  "summary": "Meeting with Client",
  "startDateTime": "2025-10-29T10:00:00+01:00",
  "endDateTime": "2025-10-29T10:45:00+01:00",
  "attendees": ["client@email.com"],
  "timeZone": "Europe/Lisbon",
  "calendarId": "primary"
}

{
  "summary": "Meeting with Client",
  "startDateTime": "2025-10-29T10:00:00+01:00",
  "endDateTime": "2025-10-29T10:45:00+01:00",
  "attendees": ["client@email.com"],
  "timeZone": "Europe/Lisbon",
  "calendarId": "primary"
}

{
  "summary": "Meeting with Client",
  "startDateTime": "2025-10-29T10:00:00+01:00",
  "endDateTime": "2025-10-29T10:45:00+01:00",
  "attendees": ["client@email.com"],
  "timeZone": "Europe/Lisbon",
  "calendarId": "primary"
}

{
  "summary": "Meeting with Client",
  "startDateTime": "2025-10-29T10:00:00+01:00",
  "endDateTime": "2025-10-29T10:45:00+01:00",
  "attendees": ["client@email.com"],
  "timeZone": "Europe/Lisbon",
  "calendarId": "primary"
}

This approach gives you full control over event date and time fields.
See: Google Calendar Tool Documentation

Source:

Google Calendar Tool Documentation

K

KyleAPP•10/30/25, 12:33 AM

Please insert this code snippet anywhere into your assistant prompt to provide correct date and times. Modify the timezone as needed:

The current date and time is {{"now" | date: "%A, %B %d, %Y, %I:%M %p", "America/Los_Angeles"}}

Do not use startTime and endTimes that are older than {{ "now" | date: "%s" | times: 1000 | tz: "America/Los_Angeles" }}

The current date and time is {{"now" | date: "%A, %B %d, %Y, %I:%M %p", "America/Los_Angeles"}}

Do not use startTime and endTimes that are older than {{ "now" | date: "%s" | times: 1000 | tz: "America/Los_Angeles" }}

The current date and time is {{"now" | date: "%A, %B %d, %Y, %I:%M %p", "America/Los_Angeles"}}

Do not use startTime and endTimes that are older than {{ "now" | date: "%s" | times: 1000 | tz: "America/Los_Angeles" }}

The current date and time is {{"now" | date: "%A, %B %d, %Y, %I:%M %p", "America/Los_Angeles"}}

Do not use startTime and endTimes that are older than {{ "now" | date: "%s" | times: 1000 | tz: "America/Los_Angeles" }}

More information on this can be found on the documentation: https://docs.vapi.ai/assistants/dynamic-variables#advanced-date-and-time-usage

Google Calendar Not Booking Events + Wrong Time Detected

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