subscription.trial_started

Pairs with member.trial_joined — both fire together when a subscriber starts a trial.

When this fires

A subscriber starts a trial on a trial-enabled plan — either through a cardless trial or a paid checkout that began with a trial window.

Required ability

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

Payload

{
  "id": "evt_01HX...",
  "type": "subscription.trial_started",
  "created_at": "2026-05-18T10:05:00Z",
  "api_version": "2026-05-01",
  "project_id": "prj_01HX...",
  "data": {
    "subscription_id": "sub_01HX...",
    "plan_id": "pln_01HX...",
    "subscriber_id": "usr_01HX...",
    "trial_ends_at": "2026-05-25T10:05:00Z"
  }
}

Field reference

Field	Type	Notes
`id`	string ULID	Unique event id, prefixed `evt_`. Use for idempotent processing.
`type`	string	Always `subscription.trial_started` for this event.
`created_at`	ISO 8601 timestamp	Server-side emission time.
`api_version`	string	Webhook API contract version.
`project_id`	string ULID	Project this event belongs to.
`data.subscription_id`	string ULID	Subscription identifier.
`data.plan_id`	string ULID	Plan the trial is on.
`data.subscriber_id`	string ULID	Subscriber's project-scoped user id.
`data.trial_ends_at`	ISO 8601 timestamp	When the trial window ends and conversion is attempted.

Caveats

Always paired with subscription.created and member.trial_joined for the same subscription_id.
Plans with trial_days = 0 skip this event entirely.

subscription.trial_converting — fires 24h before trial_ends_at.
subscription.trial_expired — fires if no conversion occurs.
Subscription events overview — back to family overview.