Cancel Event
Cancel an event and notify all attendees
Cancels a calendar event by setting its status to `cancelled`. Automatically sends cancellation notification emails to all attendees (both participants and hosts) with the event details, original time (in each attendee's timezone), and the cancellation reason if provided.
Requires `user_id` (your Zyntro user ID) in the JSON request body
Warning:
This endpoint uses `user_id` (your numeric Zyntro user ID) for authentication — not `api_key`. This is consistent with the reschedule and cancel flow used by the public booking UI.
Parameters
| Name | In | Type | Required | Description |
|---|---|---|---|---|
user_id |
body | string |
Yes | Your Zyntro user ID (numeric). Used to establish the database connection. |
event_id |
body | string |
Yes | The UUID of the event to cancel |
cancel_reason |
body | string |
No | Reason for cancellation. Appended to the event description and included in notification emails. |
Request Body
Content-Type: application/json
Example
json
{
"user_id": "32",
"event_id": "e7f8a9b0-c1d2-3456-e7f8-a9b0c1d23456",
"cancel_reason": "Client requested to postpone indefinitely."
}Code Samples
bash
curl -X POST https://app.zyntrohq.com/public/calendar/processCancel \
-H "Content-Type: application/json" \
-d '{"user_id": "32", "event_id": "e7f8a9b0-c1d2-3456-e7f8-a9b0c1d23456", "cancel_reason": "Client requested to postpone."}'Response
200
Event cancelled
json
{
"data": {
"event_id": "e7f8a9b0-c1d2-3456-e7f8-a9b0c1d23456",
"cancelled_at": "2026-04-03 14:30:00",
"notifications_sent": 3
},
"status": "success"
}
200
Already cancelled
json
{
"data": [
"Event is already cancelled"
],
"status": "error"
}
200
Not found
json
{
"data": [
"Event not found"
],
"status": "error"
}
Info:
Cancellation emails are sent from the organizer's name using the organization's configured email domain. Each attendee receives the event time formatted in their own timezone. The cancellation reason is included in both the email and the event description (appended with a separator).
Errors
| Code | Message | Resolution |
|---|---|---|
MISSING_USER_ID |
Missing service instance The user_id is missing. |
Include your user ID. |
MISSING_EVENT_ID |
Missing event ID The event_id is missing. |
Include the event UUID. |
NOT_FOUND |
Event not found No event with that ID exists. |
Verify the event_id. |
ALREADY_CANCELLED |
Event is already cancelled The event has already been cancelled. |
No action needed. |
CANCEL_FAILED |
Failed to cancel event Database update failed. |
Retry the request. |
