> For clean Markdown content of this page, append .md to this URL. For the complete documentation index, see https://docs.agentmail.to/llms.txt. # Calendar Event Starting POST Reference: https://docs.agentmail.to/api-reference/webhooks/events/calendar-event-starting ## Request ### Headers - `svix-id` (string, required) — ID of webhook message. - `svix-signature` (string, required) — Signature of webhook message. - `svix-timestamp` (datetime, required) — Timestamp of webhook message. ### Payload - `type` ("event", required) - `event_type` ("calendar.event.starting", required) - `event_id` (string, required) — Stable for this date and boundary. Use it to deduplicate deliveries. - `inbox_id` (string, required) — The ID of the inbox. - `calendar_event` (CalendarEvent, required) — The event or date as it stood when the boundary was first processed. - `scheduled_at` (datetime, required) — The start this webhook is for (the event's `start_at`). ## Types ### CalendarEvent A calendar event. The same shape is used by every response, list item and webhook. `kind` says whether it is a one-off event, the definition of a recurring series, or one date of a series. - `event_id` (string, required) — ID of a calendar event. A one-off or recurring event is addressed by its UUID. One date of a recurring event is addressed by a dated ID, `_`: `_t20261015T090000` for a timed date (the original wall-clock start in the event's time zone) or `_d20261015` for an all-day date. Dated IDs are stable: moving a date keeps its original ID. - `kind` (enum, required) — What the event object represents. - `single`: a one-off event, addressed by its UUID. - `series`: the definition of a recurring event, addressed by its UUID. It carries `recurrence`; `start` and `end` describe its first date. - `instance`: one date of a recurring event, addressed by its dated ID. It carries `series_id`, `original_start` and `is_exception`. - Allowed values: `single`, `series`, `instance` - `title` (string, required) — Title of the event. - `status` (enum, required) — Status of the event. A `cancelled` event or date stays readable but sends no `calendar.event.starting` or `calendar.event.ending` webhooks (cancelling a date that is already running still sends its `calendar.event.ending`). A date cancelled by deleting its dated ID is removed from the series instead, so reading it can return `404` or `410`. - Allowed values: `confirmed`, `tentative`, `cancelled` - `all_day` (boolean, required) — Whether this is an all-day event. - `start` (string, required) — Local start time in `timezone`. For all-day events, the first day. - `end` (string, required) — Local end time in `timezone`. For all-day events, the last day (inclusive). - `timezone` (string, required) — Canonical IANA time zone name, for example `America/New_York`, `Europe/London` or `UTC`. Abbreviations such as `PST`, Windows names such as `Pacific Standard Time`, and spellings that differ from the canonical name are rejected. - `duration_mode` (enum, required) — How the event's length is kept when a date crosses a daylight-saving change. - `exact`: the event lasts the same elapsed time. Default for one-off timed events. - `nominal`: the event keeps its wall-clock end time (a 09:00 to 10:00 meeting stays 09:00 to 10:00 local time). Default for recurring timed events. All-day events are always `nominal`. - Allowed values: `nominal`, `exact` - `duration_value` (integer, required) — Length of the event, in milliseconds for timed events and in days for all-day events. - `start_at` (datetime, required) — Start as a UTC instant. This is when `calendar.event.starting` is due. - `end_at` (datetime, required) — End as a UTC instant. This is when `calendar.event.ending` is due. - `attendee_count` (integer, required) — Number of attendees. - `uid` (string, required) — iCalendar UID of the event. Invitations about this event carry the same UID. - `sequence` (integer, required) — iCalendar SEQUENCE number. It increases when a change to a one-off or series event affects what attendees see (time, status, title, description, location, recurrence or attendees). A change to a dated event increases it only when the change is sent with `send_invites`. - `source` (enum, required) — Where the event came from. `api` events were created through this API and the inbox is their organizer. `email` events were created from a calendar invitation (iMIP) received by the inbox; their organizer is the sender of the invitation. - Allowed values: `api`, `email` - `created_at` (datetime, required) — Time at which the event (or, for a date, the definition governing it) was created. - `updated_at` (datetime, required) — Time at which the event (or, for a date, the definition governing it) was last updated. - `series_id` (string, optional) — For `instance` events, the UUID of the series this date belongs to. - `original_start` (string, optional) — For `instance` events, the date's start as the series rule generated it, before any edit. - `original_start_at` (datetime, optional) — For `instance` events, `original_start` as a UTC instant. - `is_exception` (boolean, optional) — For `instance` events, `true` when this date was edited or moved, individually or by a `mode=future` change. - `description` (string, optional) — Description of the event. Omitted from agenda and instance list items. - `location` (string, optional) — Location of the event. - `metadata` (any, optional) — Your own JSON value for the event, usually an object. Never sent to attendees. Omitted from agenda and instance list items. - `recurrence` (Recurrence, optional) — For `series` events, the recurrence. - `attendees` (list of Attendee, optional) — Attendees of the event. Omitted from agenda and instance list items; `attendee_count` is always present. - `organizer_email` (string, optional) — Email address of the organizer. For `api` events, the inbox. - `origin_message_id` (string, optional) — For `email` events, the ID of the message whose invitation last created or updated the event. - `resource_revision` (integer, optional) — Present on `single` and `series` events, except agenda items and `calendar.event.starting` and `calendar.event.ending` payloads, which omit it. - `etag` (string, optional) — The event's or date's current version, also sent as the `ETag` response header. Send it in `If-Match` to make an update, delete or response conditional. Present on Get, Create, Update, Delete and Respond responses; list items and webhooks omit it. Treat it as opaque: a dated event's `etag` (`"occ-..."`) is not derived from `resource_revision`. ### Recurrence The recurrence of a series, as stored. - `rule` (string, required) — Normalized RRULE body, without the `RRULE:` prefix. - `exdates` (list of string, optional) - `rdates` (list of RecurrenceDate, optional) - `truncate_before` (string, optional) — Set when the series was ended with a `mode=future` delete: no date starting at or after this wall-clock time occurs. ### Attendee - `email` (string, required) — Email address of the attendee. Stored in lowercase. Must be unique within the event. - `name` (string, optional) — Display name of the attendee. At most 256 characters. - `status` (enum, optional) — Response status. Defaults to `needs_action`. - Allowed values: `needs_action`, `accepted`, `declined`, `tentative` - `role` (enum, optional) — Defaults to `required`. - Allowed values: `required`, `optional` - `comment` (string, optional) — Comment the attendee sent with their response. At most 4,096 UTF-8 bytes; on create or update, a longer comment is dropped rather than rejected. - `responded_at` (datetime, optional) — Time at which the attendee last responded. ### RecurrenceDate A wall-clock date or date-time, or (timed events only) a period. ### RecurrencePeriod An extra date (RDATE) given as a period. Specify exactly one of `end` or `duration`. - `start` (string, required) — A local wall-clock time without an offset, interpreted in the event's `timezone`. Timed events use `YYYY-MM-DDTHH:mm:ss` (for example `2026-10-15T09:00:00`). All-day events use `YYYY-MM-DD`. Years must be between 1900 and 9999. - `end` (string, optional) — A local wall-clock time without an offset, interpreted in the event's `timezone`. Timed events use `YYYY-MM-DDTHH:mm:ss` (for example `2026-10-15T09:00:00`). All-day events use `YYYY-MM-DD`. Years must be between 1900 and 9999. - `duration` (string, optional) — ISO 8601 duration, for example `PT30M`.