Merge pull request #299187 from spelluru/buildupdates0501

Added Webhook auth

Author: prmerger-automator[bot]

articles/event-grid/mqtt-client-authentication.md

@@ -2,7 +2,7 @@
 title: 'Azure Event Grid Namespace MQTT client authentication'
 description: 'Describes how MQTT clients are authenticated and mTLS connection is established when a client connects to Azure Event Grid’s MQTT broker feature.'
 ms.topic: concept-article
-ms.date: 01/27/2025
+ms.date: 05/01/2025
 author: Connected-Seth
 ms.author: seshanmugam
 ms.subservice: mqtt
@@ -15,7 +15,8 @@ Azure Event Grid's MQTT broker supports the following authentication modes.
 
 - Certificate-based authentication
 - Microsoft Entra ID authentication
-- OAuth 2.0 (JSON Web Token) authentication 
+- OAuth 2.0 (JSON Web Token) authentication
+- Customer Webhook authentication 
 
 ## Certificate-based authentication
 You can use Certificate Authority (CA) signed certificates or self-signed certificates to authenticate clients. For more information, see [MQTT Client authentication using certificates](mqtt-client-certificate-authentication.md).
@@ -26,7 +27,8 @@ You can authenticate MQTT clients with Microsoft Entra JWT to connect to Event G
 ## OAuth 2.0 JWT authentication 
 You can authenticate MQTT clients using JSON Web Tokens (JWT) issued by any third-party OpenID Connect (OIDC) identity provider. This authentication method provides a lightweight, secure, and flexible option for MQTT clients that aren't provisioned in Azure. For more information, see [Authenticate client using OAuth 2.0 JWT](mqtt-client-custom-jwt.md). 
 
-
+## Custom Webhook Authentication  
+Webhook authentication allows external HTTP endpoints (webhooks or functions) to authenticate MQTT connections dynamically. This method uses Entra ID JWT (JSON Web Tokens)  validation to ensure secure access. When a device or client attempts to connect, Event Grid transmits relevant connection details to the configured webhook. The webhook is responsible for evaluating the authentication request and returning a response that determines whether the connection is permitted. Additionally, the webhook can enrich the response with metadata that Event Grid will use to authorize subsequent MQTT packets, ensuring fine-grained control over actions such as topic access and message publishing. This approach enables seamless integration with custom authentication systems, identity providers, and enterprise security policies. 
 
 ## Related content
 - Learn how to [authenticate clients using certificate chain](mqtt-certificate-chain-client-authentication.md)