> ## Documentation Index
> Fetch the complete documentation index at: https://docs.upstackdata.com/llms.txt
> Use this file to discover all available pages before exploring further.

# trial_started Event

> Track when a user begins a free trial in your SaaS application.

Fires when a user begins a free trial. This is the start of your trial-to-paid conversion funnel.

## JavaScript

```javascript theme={null}
window._upstack('track', 'trial_started', {
  accountId: 'acct_abc123',
  planId: 'plan_pro_monthly',
  planName: 'Pro Plan',
  trialEndDate: '2026-03-04T14:30:00.000Z',
  trialDaysRemaining: 14
});
```

## Properties

| Property           | Type   | Required | Description                    |
| ------------------ | ------ | -------- | ------------------------------ |
| accountId          | string | Yes      | Account identifier             |
| planId             | string | Yes      | Trial plan identifier          |
| planName           | string | No       | Human-readable plan name       |
| trialEndDate       | string | No       | ISO 8601 trial expiration date |
| trialDaysRemaining | number | No       | Days until trial expires       |

## When to Fire

* After trial signup confirmation
* After trial activation in billing system
* After Stripe `customer.subscription.created` with trial

## Stripe Webhook

Maps to `customer.subscription.created` when the subscription has a trial period.