pass_series.leg_substituted

A cancelled date in a season was replaced, and one holder was moved to the replacement.

When this fires

A creator cancelled a window that a season ticket points at, a replacement was available, and one holder was moved onto it. Their season carries on at the same length.

Fires once per holder, not once per cancellation. Each holder is resettled individually because the outcomes differ: someone already holding the replacement date skips past it to the next one they do not have, and someone with no replacement available is dropped instead.

Required ability

project-subscription:view — token must carry this at mint time to subscribe an endpoint to this event.

Payload

{
  "id": "evt_01HX...",
  "type": "pass_series.leg_substituted",
  "created_at": "2026-10-18T16:40:12Z",
  "api_version": "2026-05-01",
  "project_id": "7f3d1c92-8b45-4e6a-9d21-5c8e0a4b6f13",
  "data": {
    "subscription_id": "5b7e2d40-1a86-4c39-97f2-e83d0b16c5a4",
    "subscriber_id": "2a91c4e7-6f38-4b52-8e0d-9c1a7b3f5d80",
    "plan_id": "9a4c1b58-2e37-4d80-b6f1-0c7e35a92b41",
    "from_window_id": "3d5a8c72-b016-4e94-8fa7-61c209d4e738",
    "from_starts_at": "2026-10-25T18:00:00Z",
    "from_ends_at": "2026-10-25T21:00:00Z",
    "to_window_id": "7c0b93af-4d61-42e8-95d3-18ba6e07c254",
    "to_starts_at": "2026-11-01T18:00:00Z",
    "to_ends_at": "2026-11-01T21:00:00Z",
    "was_queued": true
  }
}

Field reference

Field	Type	Notes
`id`	string ULID	Unique event id, prefixed `evt_`. Use for idempotent processing.
`type`	string	Always `pass_series.leg_substituted` for this event.
`created_at`	ISO 8601 timestamp	Server-side emission time.
`api_version`	string	Webhook API contract version.
`project_id`	string UUID	Project this event belongs to.
`data.subscription_id`	string UUID	The season ticket that was resettled.
`data.subscriber_id`	string UUID	The holder who moved.
`data.plan_id`	string UUID	The plan the windows belong to — the source pass plan, not the series.
`data.from_window_id`	string UUID	The cancelled window.
`data.from_starts_at`	ISO 8601 timestamp	Cancelled window start, always UTC.
`data.from_ends_at`	ISO 8601 timestamp	Cancelled window end, always UTC.
`data.to_window_id`	string UUID	The replacement window they now hold.
`data.to_starts_at`	ISO 8601 timestamp	Replacement start, always UTC.
`data.to_ends_at`	ISO 8601 timestamp	Replacement end, always UTC.
`data.was_queued`	boolean	Whether they still had a pending join request on the cancelled date — tapped their invite link and not yet admitted. Someone already admitted to the cancelled window reports `false` even though they tapped, because admission consumes the request.

Caveats

was_queued is the field worth branching on. A holder who was queued stays queued for the new date and is told there is nothing to do. One who was not usually gets their invite link attached — except a holder who had already been admitted to the cancelled window: they also report was_queued: false, but their access is revoked and they are told a fresh link arrives when the new window opens, so no link is attached. was_queued: false therefore covers two different situations; if you need to tell them apart, check whether the holder currently has access. If you send your own message alongside ours, match that split or you will ask half your audience to do something they have already done.
The holder is never moved onto a date they already hold. The next one they do not have is chosen instead, so to_window_id can be further out than the immediate next window.
Three groups are skipped entirely and produce no event: holders who are paused, past due, or who cancelled their own series. They still paid for a date that is not happening. Check subscriptions on that plan before reaching for a refund list.
plan_id is the source plan. To identify the series, read subscription_id.

pass.holder_moved — the same resettlement on an ordinary single-window pass rather than a series.
pass_series.leg_dropped — what happens when no replacement exists.
pass.window_cancelled — fires once, last, carrying both tallies.
Pass series events overview — back to family overview.