Jaliya's Blog: Sending messages to Azure Service Bus from Azure API Management

Wednesday, February 4, 2026

Sending messages to Azure Service Bus from Azure API Management

With Azure API Management (APIM), now you can send/publish messages directly to Azure Service Bus. Note: at the time of writing this post, this feature is still in preview. I am very excited for this feature, because now we can have a simple architecture, we don't need a separate backend code/service to send/publish messages.

This is done via the send-service-bus-message policy.

Let's have a look.

I have a Service Bus namespace and a user assigned Managed Identity. The Managed Identity has the Azure Service Bus Data Sender role assigned to the namespace. In the Service Bus namespace, I have a topic: sbt-apim.

In my APIM, I have an API with an operation configured with the following policy.

<!-- Add policies as children to the <inbound>, <outbound>, <backend>, and <on-error> elements -->
<policies>
  <!-- Throttle, authorize, validate, cache, or transform the requests -->
  <inbound>
    <send-service-bus-message 
      topic-name="sbt-apim" 
      namespace="<ServiceBusNamespaceName>.servicebus.windows.net" 
      client-id="<ManagedIdentityClientId>">
      <message-properties>
        <message-property name="TenantId">@(context.Request.Headers.GetValueOrDefault("x-tenantId",""))</message-property>
      </message-properties>
      <payload>
        @(context.Request.Body.As<string>(preserveContent: true))
      </payload>
    </send-service-bus-message>
    <return-response>
      <set-status code="202" reason="Accepted" />
      <set-header name="Content-Type" exists-action="override">
        <value>application/json</value>
      </set-header>
      <set-body>{ "status": "Message Accepted" }</set-body>
    </return-response>
  </inbound>
  <!-- Control if and how the requests are forwarded to services  -->
  <backend>
    <base />
  </backend>
  <!-- Customize the responses -->
  <outbound>
    <base />
  </outbound>
  <!-- Handle exceptions and customize error responses  -->
  <on-error>
    <base />
  </on-error>
</policies>

Here I am using the send-service-bus-message policy in the inbound section to publish messages to a Service Bus topic. The client-id refers to the user assigned Managed Identity. You can also add custom message properties. Here I am passing the value of x-tenantId header as a custom property for demo purposes. Since we don't need a backend service, I am using return-response to immediately return a 202 Accepted response.

Let's test this.

curl 'https://<APIM_BASE_URL>/messaging/publish' `
--header 'x-tenantId: cfecb449-b568-4d0f-b24f-ea9762fb2bf6' `
--header 'Content-Type: application/json' `
--data '{
    "firstName": "John",
    "lastName": "Doe"
}'