Authorize requests to Azure SignalR resources with Managed identities for Azure resources

Article
03/14/2025

Azure SignalR Service supports Microsoft Entra ID for authorizing requests from Managed identities for Azure resources.

This article explains how to set up your resource and code to authorize requests to the resource using a managed identity.

Configure managed identities

The first step is to configure managed identities on your app or virtual machine.

Add role assignments in the Azure portal

The following steps describe how to assign a SignalR App Server role to a service principal or a managed identity for an Azure SignalR Service resource. For detailed steps, see Assign Azure roles using the Azure portal.

Note

A role can be assigned to any scope, including management group, subscription, resource group, or single resource. To learn more about scope, see Understand scope for Azure RBAC.

In the Azure portal, go to your Azure SignalR Service resource.
Select Access control (IAM) in the sidebar.
Select Add > Add role assignment.

On the Role tab, select SignalR App Server or other SignalR built-in roles depends on your scenario.

Role	Description	Use case
SignalR App Server	Access to the server connection creation and key generation APIs.	Most commonly used for app server with Azure SignalR resource run in Default mode.
SignalR Service Owner	Full access to all data-plane APIs, including REST APIs, the server connection creation, and key/token generation APIs.	For negotiation server with Azure SignalR resource run in Serverless mode, as it requires both REST API permissions and authentication API permissions.
SignalR REST API Owner	Full access to data-plane REST APIs.	For using Azure SignalR Management SDK to manage connections and groups, but does NOT make server connections or handle negotiation requests.
SignalR REST API Reader	Read-only access to data-plane REST APIs.	Use it when write a monitoring tool that calls readonly REST APIs.

Select Next.
For Microsoft Entra application.
1. In the Assign access to row, select User, group, or service principal.
2. In the Members row, click select members, then choose the identity in the pop-up window.
For managed identity for Azure resources.
1. In the Assign access to row, select Managed identity.
2. In the Members row, click select members, then choose the application in the pop-up window.
Select Next.
Review your assignment, then click Review + assign to confirm the role assignment.

Important

Newly added role assignments might take up to 30 minutes to propagate.

To learn more about how to assign and manage Azure roles, see these articles:

Configure Microsoft.Azure.SignalR app server SDK for C#

Azure SignalR server SDK for C#

The Azure SignalR server SDK leverages the Azure.Identity library to generate tokens for connecting to resources. Click to explore detailed usages.

Use system-assigned identity

services.AddSignalR().AddAzureSignalR(option =>
{
    option.Endpoints = new ServiceEndpoint[]
    {
        new ServiceEndpoint(new Uri("https://<resource-name>.service.signalr.net"), new ManagedIdentityCredential()),
    };
});

Use user-assigned identity

Important

Use the client ID, not the object (principal) ID

services.AddSignalR().AddAzureSignalR(option =>
{
    option.Endpoints = new ServiceEndpoint[]
    {
        var clientId = "<your-user-assigned-identity-client-id>";
        new ServiceEndpoint(new Uri("https://<resource-name>.service.signalr.net"), new ManagedIdentityCredential(clientId)),
    };
});

More sample can be found in this Sample link

Use multiple endpoints

Credentials can be different for different endpoints.

In this sample, the Azure SignalR SDK will connect to resource1 with system-assigned managed identity and connect to resource2 with user-assigned managed identity.

services.AddSignalR().AddAzureSignalR(option =>
{
    option.Endpoints = new ServiceEndpoint[]
    {
        var clientId = "<your-user-assigned-identity-client-id>";
        new ServiceEndpoint(new Uri("https://<resource1>.service.signalr.net"), new ManagedIdentityCredential()),
        new ServiceEndpoint(new Uri("https://<resource2>.service.signalr.net"), new ManagedIdentityCredential(clientId)),
    };
});

Azure SignalR Service bindings in Azure Functions

Azure SignalR Service bindings in Azure Functions use application settings in the portal or local.settings.json locally to configure a managed identity to access your Azure SignalR Service resources.

You might need a group of key/value pairs to configure an identity. The keys of all the key/value pairs must start with a connection name prefix (which defaults to AzureSignalRConnectionString) and a separator. The separator is an underscore (__) in the portal and a colon (:) locally. You can customize the prefix by using the binding property ConnectionStringSetting.

Use a system-assigned identity

If you configure only the service URI, you use the DefaultAzureCredential class. This class is useful when you want to share the same configuration on Azure and local development environments. To learn how it works, see DefaultAzureCredential.

In the Azure portal, use the following example to configure DefaultAzureCredential. If you don't configure any of these environment variables, the system-assigned identity is used for authentication.

<CONNECTION_NAME_PREFIX>__serviceUri=https://<SIGNALR_RESOURCE_NAME>.service.signalr.net

Here's a configuration sample of DefaultAzureCredential in the local.settings.json file. At the local scope, there's no managed identity. Authentication via Visual Studio, the Azure CLI, and Azure PowerShell accounts is attempted in order.

{
  "Values": {
    "<CONNECTION_NAME_PREFIX>:serviceUri": "https://<SIGNALR_RESOURCE_NAME>.service.signalr.net"
  }
}

If you want to use a system-assigned identity independently and without the influence of other environment variables, set the credential key with the connection name prefix to managedidentity. Here's a sample for application settings:

<CONNECTION_NAME_PREFIX>__serviceUri = https://<SIGNALR_RESOURCE_NAME>.service.signalr.net
<CONNECTION_NAME_PREFIX>__credential = managedidentity

Use a user-assigned identity

If you want to use a user-assigned identity, you need to assign clientId in addition to serviceUri and credential keys with the connection name prefix. Here's a sample for application settings:

<CONNECTION_NAME_PREFIX>__serviceUri = https://<SIGNALR_RESOURCE_NAME>.service.signalr.net
<CONNECTION_NAME_PREFIX>__credential = managedidentity
<CONNECTION_NAME_PREFIX>__clientId = <CLIENT_ID>

Next steps

See the following related articles:

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