Payload

All webhook payloads follow a consistent top-level structure with event-specific data nested within the data object.

subscriptionIdstring

The subscription ID.

customerIdstring

The customer ID. Returns your externalId if you provided one when creating the customer, otherwise returns the Commet publicId.

statusstring

Always "trialing" for this event.

planIdstring

The plan ID.

planNamestring

The plan name.

trialEndsAtstring

ISO 8601 datetime when the trial will end.

{
  "event": "trial.will_end",
  "timestamp": "2026-04-05T06:00:00.000Z",
  "organizationId": "org_abc123",
  "mode": "live",
  "apiVersion": "2026-05-25",
  "data": {
    "subscriptionId": "sub_1a2b3c4d",
    "customerId": "user_123",
    "status": "trialing",
    "planId": "plan_pro_monthly",
    "planName": "Pro",
    "trialEndsAt": "2026-04-08T00:00:00.000Z"
  }
}

When this fires

A daily scan finds trials ending within the next 3 days and emits this event once per trial. The idempotency key is derived from the subscription and the trial end date, so re-running the scan never sends a duplicate.

Use it to remind the customer that billing starts on trialEndsAt — the single most effective moment to prevent involuntary churn and surprise charges.

If the trial end date changes after this event fired (for example, the customer converts early), trial.converted or trial.expired reflects the final outcome.