You can add custom attributes to a Conversation object in the chat SDK with the conversation id and the custom attribute key-value pair.
## Required attributes
| Name | Type | Description |
`id` | String | The unique ID for the conversation in Kustomer. |
`["customAttributeNameType": <custom attribute value>]` | Array of key-value pairs | An array containing the custom attributes of the conversation.
Example: `["favoriteNumberNum":100]` |
## Use custom attributes
You can send the SDK custom attribute values for custom attributes enabled in Kustomer.
**Always** use the attribute name instead of the Display Name listed in the Klasses editor (**Settings > Platform > Klasses**) in Kustomer. The attribute name will always be formatted in camelCase or PascalCase without spaces and also describes the data type for the attribute.
For example, if a custom attribute has a Display Name of "Avg Sat Score" and has a number data type, then the name may appear as `AvgSatScoreNum`. You would use `AvgSatScoreNum`, the system name for the custom attribute, with the SDK.
Activate custom attributes for the Conversation klass
To update custom attributes, ensure you have the custom attribute key-value pairs activated for the Conversation klass on the Kustomer platform. To edit or view custom attributes for the Customer klass, go to **Settings** and select** Platform > Klasses > Conversation**.
To learn more, see [Define custom attribute in Kustomer](🔗) in the Kustomer Help Center.
Always send in the system name for custom attributes and check that the attribute is activated in the Klasses editor.