HTTP headers

Webhook updates include a set of HTTP headers, some of which are standard HTTP headers and some of which are Toast-specific. This section provides more details on both types.

Toast-specific HTTP headers

The following table describes the Toast-specific HTTP headers included with webhook events.

Header	Description
`Toast-Signature`	As a security measure, all webhook messages contain a signature in the `Toast-Signature` HTTP header. A webhook endpoint uses the `Toast-Signature` header to confirm that a webhook update message is coming from a known, secure source. See Message signing for more details.
`Toast-Event-Type`	The type of event that has occurred, for example, a `partner_added` event for the `partners` webhook or a `low_quantity` event for the `stock` webhook.
`Toast-Restaurant-External-ID`	If the triggering event has occurred at a restaurant, the GUID of that restaurant is included in the `Toast-Restaurant-External-ID` HTTP header, for example, if the webhook update is for a `low_quantity` event, this header identifies the restaurant where the inventory quantity is low. This header is omitted if the triggering event has not occurred at a restaurant, for example, the header is omitted for the Partners webhook event types because those events are triggered by changes to a partner's status, not changes to a restaurant's status.
`Toast-Event-Category`	The event category, for example, `partners` or `stock`.

Standard HTTP headers

In addition to the Toast-specific HTTP headers, webhook events include the standard HTTP headers shown in the table below. For more detailed information on these headers, see https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers:

Header	Value
`Accept-Encoding`	`gzip,deflate`
`Connection`	`close`
`Content-Length`	The size of the message body, in bytes.
`Content-Type`	`application/json`
`Host`	The domain name and port of the server that is listening for webhook events. Generated from the partner URI that is specified when a webhook subscription is created.
`User-Agent`	`Apache-HttpClient/4.5.10 (Java/1.8.0_212)`