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Configures Keycloak as the authentication provider for ASP.NET Core applications.

Published
Aug 21, 2026
1mo ago
Total Downloads
673.0K
673,033

Install

dotnet add package Aspire.Keycloak.Authentication --version 13.5.2-preview.1.26421.6
ProductVersions
.NET
net10.0net8.0net9.0

README

Aspire.Keycloak.Authentication library

Adds JwtBearer and OpenId Connect authentication to the project via a Keycloak.

Getting started

Prerequisites

  • A Keycloak server instance
  • A Keycloak realm
  • For JwtBearer authentication, a configured audience in the Keycloak realm
  • For OpenId Connect authentication, the ID of a client configured in the Keycloak realm

Install the package

Install the Aspire Keycloak library with NuGet:

dotnet add package Aspire.Keycloak.Authentication

Jwt bearer authentication usage example

In the Program.cs file of your ASP.NET Core API project, call the AddKeycloakJwtBearer extension method to add JwtBearer authentication, using a connection name, realm and any required JWT Bearer options:

builder.Services.AddAuthentication()
                .AddKeycloakJwtBearer("keycloak", realm: "WeatherShop", options =>
                {
                    options.Audience = "weather.api";
                });

You can set many other options via the Action<JwtBearerOptions> configureOptions delegate.

OpenId Connect authentication usage example

In the Program.cs file of your Blazor project, call the AddKeycloakOpenIdConnect extension method to add OpenId Connect authentication, using a connection name, realm and any required OpenId Connect options:

builder.Services.AddAuthentication(OpenIdConnectDefaults.AuthenticationScheme)
                .AddKeycloakOpenIdConnect(
                    "keycloak", 
                    realm: "WeatherShop", 
                    options =>
                    {
                        options.ClientId = "WeatherWeb";
                        options.ResponseType = OpenIdConnectResponseType.Code;
                        options.Scope.Add("weather:all");
                    });

You can set many other options via the Action<OpenIdConnectOptions>? configureOptions delegate.

AppHost extensions

In your AppHost project, install the Aspire.Hosting.Keycloak library with NuGet:

dotnet add package Aspire.Hosting.Keycloak

Then, in the AppHost.cs file of AppHost, register a Keycloak server and consume the connection using the following methods:

var keycloak = builder.AddKeycloak("keycloak", 8080);

var apiService = builder.AddProject<Projects.Keycloak_ApiService>("apiservice")
                        .WithReference(keycloak);

builder.AddProject<Projects.Keycloak_Web>("webfrontend")
       .WithExternalHttpEndpoints()
       .WithReference(keycloak)
       .WithReference(apiService);

Recommendation: For local development use a stable port for the Keycloak resource (8080 in the example above). It can be any port, but it should be stable to avoid issues with browser cookies that will persist OIDC tokens (which include the authority URL, with port) beyond the lifetime of the AppHost.

The WithReference method configures a connection in the Keycloak.ApiService and Keycloak.Web projects named keycloak.

In the Program.cs file of Keycloak.ApiService, the Keycloak connection can be consumed using:

builder.Services.AddAuthentication()
                .AddKeycloakJwtBearer("keycloak", realm: "WeatherShop");

And in the Program.cs file of Keycloak.Web, the Keycloak connection can be consumed using:

var oidcScheme = OpenIdConnectDefaults.AuthenticationScheme;

builder.Services.AddAuthentication(oidcScheme)
                .AddKeycloakOpenIdConnect(
                    "keycloak", 
                    realm: "WeatherShop", 
                    oidcScheme);

Additional documentation

Feedback & contributing

https://github.com/microsoft/aspire

Changes from Previous Version

No structural changes between v13.5.1-preview.1.26420.4 and v13.5.2-preview.1.26421.6.

Adoption Assessment

A verified publisher signal is available. Assess fit from the package's supported frameworks, license and dependency graph rather than popularity alone.

This version is marked prerelease. Validate its API and upgrade path before production use.Compatibility metadata lists 3 target frameworks; confirm the exact target used by your application.

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