member.trial_joined

Like member.joined, this event covers zero-payment acquisition only. A paid checkout that starts in a trial does not emit it.

When this fires

Two paths emit this event:

Cardless trial start — a subscriber begins a trial that took no payment method.
Access-code redemption on a trial plan — the redeemed plan sets trial_ends_at, so this fires in place of member.joined.

A Stripe checkout that begins with a trial window emits subscription.activated and subscription.trial_started, but no member.* join event.

Required ability

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

Payload

The data keys differ by path. Absent keys are omitted entirely, not sent as null.

Cardless trial start

{
  "id": "evt_01HX...",
  "type": "member.trial_joined",
  "created_at": "2026-05-18T10:05:00Z",
  "api_version": "2026-05-01",
  "project_id": "7f3d1c92-8b45-4e6a-9d21-5c8e0a4b6f13",
  "data": {
    "subscription_id": "5b7e2d40-1a86-4c39-97f2-e83d0b16c5a4",
    "plan_id": "c4e82f16-93a7-4d5b-b81c-6e0f27a94d3b",
    "subscriber_id": "2a91c4e7-6f38-4b52-8e0d-9c1a7b3f5d80",
    "trial_ends_at": "2026-05-25T10:05:00Z"
  }
}

Access-code redemption on a trial plan

{
  "id": "evt_01HX...",
  "type": "member.trial_joined",
  "created_at": "2026-05-18T10:05:00Z",
  "api_version": "2026-05-01",
  "project_id": "7f3d1c92-8b45-4e6a-9d21-5c8e0a4b6f13",
  "data": {
    "subscription_id": "5b7e2d40-1a86-4c39-97f2-e83d0b16c5a4",
    "project_id": "7f3d1c92-8b45-4e6a-9d21-5c8e0a4b6f13",
    "plan_id": "c4e82f16-93a7-4d5b-b81c-6e0f27a94d3b",
    "subscriber_id": "2a91c4e7-6f38-4b52-8e0d-9c1a7b3f5d80",
    "access_code": "TRIAL-7C1B4"
  }
}

Field reference

Field	Type	Notes
`id`	string ULID	Unique event id, prefixed `evt_`. Use for idempotent processing.
`type`	string	Always `member.trial_joined` 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	Subscription that triggered the join.
`data.plan_id`	string UUID	Plan the subscription is on.
`data.subscriber_id`	string UUID	Subscriber's project-scoped user id.
`data.trial_ends_at`	ISO 8601 timestamp	Cardless-trial path only.
`data.project_id`	string UUID	Access-code path only. Mirrors the envelope `project_id`.
`data.access_code`	string	Access-code path only. The full redeemed code, not masked.

Caveats

A trial-joined member emits member.converted if the trial converts to paid, or rolls into member.churned once the trial expires without converting.
member.converted is currently emitted for Stripe only. Trials taken through other providers will not produce a conversion event.
subscription.created and subscription.trial_started fire alongside this event on both paths.

subscription.trial_started — fires alongside.
member.converted — fires on successful trial conversion (Stripe only).
member.joined — non-trial counterpart.
Member events overview — back to family overview.