---
schema_version: "1"
id: 4522ddd14c13282b33f0d2dc5f938d3c4c1c53052bae8bd9886661228ee5a078
title: Register a New Callback for Event Notifications
collection: admin
version: current
locale: en-us
portal_url: https://docs.salesforce.com/admin/current/en-us/mktg/264-0-0/mc_overview_ens_register_callback.md
canonical_url: https://help.salesforce.com/s/articleView?id=mktg.mc_overview_ens_register_callback.htm&release=264.0.0&type=5
source_site: help.salesforce.com
content_type: documentation
content_hash: 08052e5e3eac986a5ce00f7ece0289a78f49480dddd44ac084f5233351d9f101
description: Follow these steps to register a new callback for event notifications in Marketing Cloud Engagement.
products:
  - Marketing
  - Marketing Cloud Engagement
release: "264"
---
# Register a New Callback for Event Notifications

Follow these steps to register a new callback for event notifications in Marketing Cloud Engagement.

1. In Marketing Cloud Engagement Setup, in the Quick Find Box, enter callbacks and then select **URL Callbacks**.
2. Click **Register New**.
3. Enter a name, URL, and maximum batch size for the callback.
4. Save the callback.
    
    Marketing Cloud Engagement sends a POST request to the URL for the callback. The request contains a JSON object with a `callbackId` value and a `verificationKey` value, as shown in this example.
    
    ```
    {
      "callbackId": "fd5f6273-5505-49ba-b094-c7a99b086e33",
      "verificationKey": "3py0I4jawlzoUNAEB1he4Dn9foUdT9yQZWtTexamP1e0="
    }
    ```
5. On the URL Callbacks page in Setup, next to the callback you created, click **Verify**.
6. In the Verification Key field, paste the verification key from the POST request that Marketing Cloud Engagement sent to your callback URL.
7. Click **Verify**.

#### See Also

- [Get Started with Event Notification Service](https://help.salesforce.com/s/articleView?id=mktg.mc_overview_ens_get_started.htm&release=264.0.0&type=5 "Configure your system to work with the Event Notification Service (ENS) in Marketing Cloud Engagement. The configuration process registers the callbacks and creates the subscriptions used to interact with your external system.")
- [Marketing Cloud Engagement APIs and Programmatic Languages: Create Callback](https://developer.salesforce.com/docs/marketing/marketing-cloud/references/mc_rest_event_notification/createCallback.html)
- [Marketing Cloud Engagement APIs and Programmatic Languages: Verify Callback](https://developer.salesforce.com/docs/marketing/marketing-cloud/references/mc_rest_event_notification/verifyCallback.html)