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

# Custom events

> Track actions that matter to your product or funnel.

Use a custom event when the SDK cannot infer an important action automatically: a signup, lead submission, trial start, upgrade, or feature milestone.

## Design the event

Give each action a short, stable name. Use lowercase names such as `signup_completed` or `demo_booked`. Put variation in properties instead of creating dozens of event names.

```js theme={null}
datalyr.track("signup_completed", {
  plan: "pro",
  billing_period: "annual"
})
```

For a purchase-like event, send numeric value and an ISO currency when supported by the SDK and your conversion rule.

```js theme={null}
datalyr.track("order_completed", {
  order_id: "ord_4821",
  value: 79,
  currency: "USD"
})
```

Use the exact method and options from the relevant **SDK Reference**. Server and mobile SDKs can also support original timestamps or idempotency values for delayed and retryable events.

## Verify it

1. Deploy to a test environment.
2. Perform the action once with a known test user.
3. Find the event in **Events**.
4. Confirm its name, identity, timestamp, and required properties.
5. If it drives a destination conversion, create the rule only after the source event is correct.

## Keep the schema clean

* Never put IDs or dynamic values in the event name.
* Keep property types consistent; do not alternate between `79` and `"79"`.
* Use a stable order or transaction ID to prevent accidental duplicate business events.
* Document required properties in your application repository.

<Warning>
  Do not include passwords, tokens, complete payment details, or regulated personal data in custom properties.
</Warning>