> This page is part of the [Customer.io documentation](https://docs.customer.io). For the complete index, see [llms.txt](https://docs.customer.io/llms.txt).
> Last updated: September 14, 2026
> To take actions in Customer.io from an agent, use the [Customer.io CLI](https://docs.customer.io/ai/cli/get-started.md) or the [MCP server](https://docs.customer.io/ai/mcp/get-started.md).

# Track events

Events are things people do in your app. They help you track your audience's behaviors, activity, and metrics. You can use them to segment your audience, trigger messaging automations, and see how people use your app.

## Track an event

The `track` method helps you send events representing your audience’s activities to Customer.io. When you send events, you can include event `properties`—information about the person or the event that they performed.

In Customer.io, you can use events to trigger automations and broadcasts. Those automations might send someone a push notification or manipulate information associated with the person in your workspace.

Events include the following:

*   `name` (Required): The name of the event. Most event-based searches in Customer.io hinge on the name, so make sure that you provide an event name that will make sense to other members of your team.
*   `properties` (Optional): Additional information that you want to reference in messages or use to segment your audience, etc. You can reference event properties in messages and other workflow actions using [liquid](/journeys/liquid/using-liquid) in the format `{{event.<properties>}}`.

```
CustomerIO.instance.track(name: "add-to-cart", properties: {"product": "shoes", "price": "29.99"});
```

### Anonymous activity

If you send a `track` call before you `identify` a person, we’ll attribute the event to an `anonymousId`. When you identify the person, we’ll reconcile their anonymous activity with the identified person.

When we apply anonymous events to an identified person, the previously anonymous activity becomes eligible to trigger automations in Customer.io.

## Semantic Events

Some actions don’t map cleanly to our simple `identify`, `track`, and other calls. For these, we use “semantic events,” events that have a special meaning in Customer.io and your destinations.

These are especially important in Customer.io for destructive operations like deleting a person. When you send an event with a semantic `event` name, we’ll perform the appropriate action.

For example, if a person decides to leave your service, you might delete them from your workspace. In Customer.io, you’ll do that with a `Delete Person` event.

For example, you can associate a person with a group (called an [object](/messaging/objects-data/objects/start/) in Customer.io) with a simple `group` call. But what if you wanted to remove someone from the group? In Customer.io, you do that with an event called `Relationship Deleted`.

```
CustomerIO.instance.track(name: "User Deleted)
```

[GitHub project](https://github.com/customerio/customerio-flutter "View the Flutter SDK on GitHub")

Version

4.7.2 (Current)2.x (2.9.0)1.x (1.5.2)

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