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

# User attributes

> [!NOTE]
>
> **Prerequisites**
>
> * [Castled SDK is installed and initialised](https://docs.castled.io/developer-resources/sdk-integration/php/getting-started.md)

Use the `identify` static method in Castled SDK to create/update users with their unique traits. The data sent via identify will be stored in your data warehouse.

```php
Castled::identify([
        'userId' => '12345',
        'traits' => [
            'plan' => 'basic',
            'first_name' => 'John',
            'last_name' => 'Taylor'
        ]
    ]);
```


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