pass_series.seats_exhausted

When this fires

A purchase took the last seat on a series with a Seat Limit. The season is now sold out — its portal card reads Sold out, but a checkout already in flight is not blocked — the seat cap is only claimed once the payment lands, so a late buyer can pay, be given nothing, and be told to ask the organiser for a refund. Treat this event as the cue to stop promoting the season yourself.

Fires at the transition, once. An endpoint told this on every subsequent read would be told a fact rather than an event.

Required ability

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

Payload

{
  "id": "evt_01HX...",
  "type": "pass_series.seats_exhausted",
  "created_at": "2026-09-12T14:22:51Z",
  "api_version": "2026-05-01",
  "project_id": "7f3d1c92-8b45-4e6a-9d21-5c8e0a4b6f13",
  "data": {
    "plan_id": "c4e82f16-93a7-4d5b-b81c-6e0f27a94d3b",
    "plan_name": "Autumn Season Ticket",
    "seat_cap": 50,
    "seats_taken": 50,
    "last_subscription_id": "5b7e2d40-1a86-4c39-97f2-e83d0b16c5a4"
  }
}

Field reference

Field	Type	Notes
`id`	string ULID	Unique event id, prefixed `evt_`. Use for idempotent processing.
`type`	string	Always `pass_series.seats_exhausted` for this event.
`created_at`	ISO 8601	Server-side emission time.
`api_version`	string	Webhook API contract version.
`project_id`	string UUID	Project this event belongs to.
`data.plan_id`	string UUID	The series plan that sold out.
`data.plan_name`	string	Its name.
`data.seat_cap`	integer	The limit that was reached.
`data.seats_taken`	integer	Holders counted against it.
`data.last_subscription_id`	string UUID	The purchase that took the final seat.

Caveats

Sold out is not permanent. A seat is released when a holder cancels or is refunded, and the series goes back on sale — at which point a later purchase can exhaust it again and emit this a second time. Treat it as a state change, not a terminal state.
Only holders who actually hold the series consume a seat. A checkout that was started and abandoned, or a payment that never cleared, does not.
A series with no Seat Limit never emits this at all.
Raising the cap does not emit anything. If you are tracking availability, read seats_remaining on the plan rather than inferring it from this event alone.

pass_series.purchased — every purchase, each carrying seats_remaining.
plan.deactivated — the series coming off sale for good once its dates have run.
Pass series events overview — back to family overview.