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Note

Optimizely Forms is only supported by MVC-based websites and HTML5-compliant browsers.

A **WebHook** is a simple event notification via HTTP POST; when a WebHook event is triggered, a HTTP POST request is sent to a URL.

Optimizely has built-in WebHooks, inspired by [GitHub webhook specs](🔗). As a publisher of the event, WebHooks rings the bell of remote URL, push enough information and send the payload away.

Instead of customizing the URL in edit view (as a site administrator), customize the URL as a developer by implementing a receiver to handle the incoming `HttpRequest` to process the data; take the data structure directly in `HttpHandler`, and consume it. It is developer-friendly and less error-prone than managing two places (URL in the edit view and a handler in the receiver code).

The default `WebHookActor` supports a list of several WebHook URLs to send out the payload.

## Configure data format

Use the [serializingObjectUsingNameValueFormat](🔗) key (in the _Forms.config_ file) to set up the kind of data format used before sending data to WebHook receiver.

## Supported data format

WebHook receivers are sent in two types of data formats:

• **Key-value dictionary** format – Pairs of key-value are sent to WebHook Receivers. Keys are the name of the element blocks of a form, and values are supplied by users.

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• **JSON object** format – A JSON object, containing all form data, is sent to WebHook receivers. Keys of the JSON object are the name of element blocks of the form. JSON object format is the default format.

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When a form container is edited and some element blocks are permanently deleted, the submission data might still contain: **{"key":"\_\_field\_1078","value":""},**

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Limitation

Because of using the block's name as the field name in `SubmissionData`, a unique field name is not guaranteed. An editor might name several blocks with same name and it might cause confusion for the WebHook receiver.