---
title: "Send additional event data"
slug: "send-additional-event-data"
abstract: "Describes sending additional event data (Sitecore CDP Stream API)."
---
# Send additional event data

::::tabs
:::tab{title="2.1"}

You can supply additional data with an event by using the `ext` data extension object.

The following is a list of guidelines for using the events data extension:

- Only one data extension is supported per event type.
- The name of the event data extension object must be `ext`.
- An event data extension object can have a maximum of 50 attributes.

The following is a list of guidelines for using attributes in the `ext` data extension object:

- The attribute name must be alphanumeric \[A-Z,a-z,0-9\] as per the [JSON RFC 7159](https://www.rfc-editor.org/rfc/rfc7159) specification.
- You must write the attribute name of the data extension in camel case.
- The attribute name must be unique within the entire event type.
- We recommend making the attribute name meaningful.

    Consider using the `friendlyID`.

- If grouping is required, use common prefixes.

The following table contains the required query parameters:

| Attribute | Description |
| --- | --- |
| `ext` | A JSON object of event extension data. |
| `ext.attribute` | Name-value pairs for custom data. The name must follow the attribute naming guidelines specified. The following are supported data types for the value:<br><br><ul><li>string: `"Hello"`</li><li>Boolean: `true` or `false`</li><li>integer: `9`</li><li>float: `99.9`</li></ul> |

> [!warning]
> You must not use the same attribute name with different data types when sending a specific event type (for example, VIEW and IDENTITY).
>
> For example, if you send a VIEW event, ensure that the data type you use for the attribute value in the `ext` object is consistent across all VIEW events.

Example 57. VIEW event data including the `ext` object

```json
{
  "type": "VIEW",
  "channel": "WEB",
  "pos": "myretailsite/ireland",
  "browser_id": "a38b230c-11eb-4cf9-8d5d-274e9f344925​",
  "language": "EN",
  "currency": "EUR",
  "page": "home page",
  "ext": {
    "tileRef": 17
  }
}

```

Example 58. Conflict when sending a VIEW event

The two examples describe a conflict when sending a VIEW event. The conflict occurs because the same attribute name (`status`) contains an integer value in the first example, but a string value in the second example.

```json
{
   "type":"VIEW",
   "ext":{
      "status": 0
   }
}

```

```json
{
   "type":"VIEW",
   "ext":{
      "status": "OK"
   }
}

```

:::
:::tab{title="2.0"}

2.0 data model does not support this functionality.

:::::::