# Sending CloudEvents events to API destinations
<a name="eb-api-destinations-cloudevents"></a>

CloudEvents is a vendor-neutral specification for event formatting, with the goal of providing interoperability across services, platforms and systems. You can use EventBridge to transform AWS service events to CloudEvents before they are sent to a target, such as an API destination.

**Note**  
The following procedure explains how to transform source events into *structured-mode* CloudEvents. In the CloudEvents specification, a structured-mode message is one where the entire event (attributes and data) is encoded into the payload of the event.

For more information on the CloudEvents specification, see [cloudevents.io](https://cloudevents.io/).

**To transform AWS events to the CloudEvents format using the console**

To transform events to the CloudEvents format prior to delivery to a target, you start by creating an event bus rule. As part of defining the rule, you use an input transformer to have EventBridge transform events prior to sending to the target you specify.

1. Follow the steps in the [Creating rules using the Enhanced Builder](eb-create-rule-visual.md) procedure.

1. In the [Select targets](eb-create-rule-wizard.md#eb-create-rule-target) step, when prompted to choose an API destination as the target type:

   1. Select **EventBridge API destination**.

   1. Do one of the following:
      + Choose **Use an existing API destination** and select an existing API destination
      + Choose **Create a new API destination** and specify the necessary setting to define your new API destination.

        For more information on specifying the required settings, see [Create an API destination in Amazon EventBridge](eb-api-destination-create.md).

   1. Specify the necessary Content-Type header parameters for the CloudEvents events:
      + Under **Header Parameters** choose **Add header parameter**.
      + For **key**, specify `Content-Type`. 

        For **value**, specify `application/cloudevents+json; charset=UTF-8`.

1. Specify an execution role for your target.

1. Define an input transformer to transform the source event data into the CloudEvents format:

   1. Under **Additional settings**, for **Configure target input**, choose **Input transformer**.

      Then choose **Configure input transformer**.

   1. Under **Target input transformer**, specify the **Input path**.

      In the input path below, the region attribute is a custom *extension attribute* of the CloudEvents format. As such it is not required for adherence to the CloudEvents specification.

      CloudEvents allows you to use and create extension attributes not defined in the core specification. For more information, including a list of known extension attributes, see [CloudEvents Extension Attributes](https://github.com/cloudevents/spec/tree/main/cloudevents/extensions) in the [CloudEvents specification documentation](https://github.com/cloudevents/spec/tree/main) on GitHub.

      ```
      {
        "detail": "$.detail",
        "detail-type": "$.detail-type",
        "id": "$.id",
        "region": "$.region",
        "source": "$.source",
        "time": "$.time"
      }
      ```

   1. For **Template**, enter the template to transform the source event data to the CloudEvents format. 

      In the template below, `region` is not strictly required, since the `region` attribute in the input path is an extension attribute to the CloudEvents specification.

      ```
      {
        "specversion":"1.0",
        "id":<id>,
        "source":<source>,
        "type":<detail-type>,
        "time":<time>,
        "region":<region>,
        "data":<detail>
      }
      ```

1. Complete creating the rule following the [procedure steps](eb-create-rule-visual.md).