Quarkus - Using OpenID Connect and Keycloak to Centralize Authorization

This guide demonstrates how your Quarkus application can authorize a bearer token access to protected resources using Keycloak Authorization Services.

The quarkus-keycloak-authorization extension is based on quarkus-oidc and provides a policy enforcer that enforces access to protected resources based on permissions managed by Keycloak and currently can only be used with the Quarkus OIDC service applications. It provides a flexible and dynamic authorization capability based on Resource-Based Access Control. In other words, instead of explicitly enforcing access based on some specific access control mechanism (e.g.: RBAC), you just check whether or not a request is allowed to access a resource based on its name, identifier or URI.

By externalizing authorization from your application, you are allowed to protect your applications using different access control mechanisms as well as avoid re-deploying your application every time your security requirements change, where Keycloak will be acting as a centralized authorization service from where your protected resources and their associated permissions are managed.

See the Using OpenID Connect to Protect Service Applications guide for more information about Bearer Token authentication mechanism.

If you are already familiar with Keycloak, you’ll notice that the extension is basically another adapter implementation but specific for Quarkus applications. Otherwise, you can find more information in the Keycloak documentation.


To complete this guide, you need:

  • less than 15 minutes

  • an IDE

  • JDK 1.8+ installed with JAVA_HOME configured appropriately

  • Apache Maven 3.6.2+

  • jq tool

  • Keycloak

  • Docker


In this example, we build a very simple microservice which offers two endpoints:

  • /api/users/me

  • /api/admin

These endpoints are protected and can only be accessed if a client is sending a bearer token along with the request, which must be valid (e.g.: signature, expiration and audience) and trusted by the microservice.

The bearer token is issued by a Keycloak Server and represents the subject to which the token was issued for. For being an OAuth 2.0 Authorization Server, the token also references the client acting on behalf of the user.

The /api/users/me endpoint can be accessed by any user with a valid token. As a response, it returns a JSON document with details about the user where these details are obtained from the information carried on the token. This endpoint is protected with RBAC (Role-Based Access Control) and only users granted with the user role can access this endpoint.

The /api/admin endpoint is protected with RBAC (Role-Based Access Control) and only users granted with the admin role can access it.

This is a very simple example using RBAC policies to govern access to your resources. However, Keycloak supports other types of policies that you can use to perform even more fine-grained access control. By using this example, you’ll see that your application is completely decoupled from your authorization policies with enforcement being purely based on the accessed resource.


We recommend that you follow the instructions in the next sections and create the application step by step. However, you can go right to the completed example.

Clone the Git repository: git clone https://github.com/quarkusio/quarkus-quickstarts.git, or download an archive.

The solution is located in the security-keycloak-authorization-quickstart directory.

Creating the Project

First, we need a new project. Create a new project with the following command:

mvn io.quarkus:quarkus-maven-plugin:1.13.2.Final:create \
    -DprojectGroupId=org.acme \
    -DprojectArtifactId=security-keycloak-authorization-quickstart \
    -Dextensions="oidc,keycloak-authorization,resteasy-jackson" \
cd security-keycloak-authorization-quickstart

This command generates a Maven project, importing the keycloak-authorization extension which is an implementation of a Keycloak Adapter for Quarkus applications and provides all the necessary capabilities to integrate with a Keycloak Server and perform bearer token authorization.

If you already have your Quarkus project configured, you can add the oidc and keycloak-authorization extensions to your project by running the following command in your project base directory:

./mvnw quarkus:add-extension -Dextensions="oidc,keycloak-authorization"

This will add the following to your pom.xml:


Let’s start by implementing the /api/users/me endpoint. As you can see from the source code below it is just a regular JAX-RS resource:

package org.acme.security.keycloak.authorization;

import javax.inject.Inject;
import javax.ws.rs.GET;
import javax.ws.rs.Path;

import org.jboss.resteasy.annotations.cache.NoCache;

import io.quarkus.security.identity.SecurityIdentity;

public class UsersResource {

    SecurityIdentity identity;

    public User me() {
        return new User(identity);

    public static class User {

        private final String userName;

        User(SecurityIdentity identity) {
            this.userName = identity.getPrincipal().getName();

        public String getUserName() {
            return userName;

The source code for the /api/admin endpoint is also very simple:

package org.acme.security.keycloak.authorization;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;

import io.quarkus.security.Authenticated;

public class AdminResource {

    public String admin() {
        return "granted";

Note that we did not define any annotation such as @RoleAllowed to explicitly enforce access to a resource. The extension will be responsible to map the URIs of the protected resources you have in Keycloak and evaluate the permissions accordingly, granting or denying access depending on the permissions that will be granted by Keycloak.

Configuring the application

The OpenID Connect extension allows you to define the adapter configuration using the application.properties file which should be located at the src/main/resources directory.

# OIDC Configuration

# Enable Policy Enforcement
By default, applications using the quarkus-oidc extension are marked as a service type application (see quarkus.oidc.application-type). This extension currently supports only such service type applications.

Starting and Configuring the Keycloak Server

To start a Keycloak Server you can use Docker and just run the following command:

docker run --name keycloak -e KEYCLOAK_USER=admin -e KEYCLOAK_PASSWORD=admin -p 8180:8080 -p 8543:8443 {keycloak-docker-image}

You should be able to access your Keycloak Server at localhost:8180/auth or localhost:8543/auth.

Log in as the admin user to access the Keycloak Administration Console. Username should be admin and password admin.

Import the realm configuration file to create a new realm. For more details, see the Keycloak documentation about how to create a new realm.

Running and Using the Application

Running in Developer Mode

To run the microservice in dev mode, use ./mvnw clean compile quarkus:dev.

Running in JVM Mode

When you’re done playing with "dev-mode" you can run it as a standard Java application.

First compile it:

./mvnw package

Then run it:

java -jar target/quarkus-app/quarkus-run.jar

Running in Native Mode

This same demo can be compiled into native code: no modifications required.

This implies that you no longer need to install a JVM on your production environment, as the runtime technology is included in the produced binary, and optimized to run with minimal resource overhead.

Compilation will take a bit longer, so this step is disabled by default; let’s build again by enabling the native profile:

./mvnw package -Pnative

After getting a cup of coffee, you’ll be able to run this binary directly:


Testing the Application

The application is using bearer token authorization and the first thing to do is obtain an access token from the Keycloak Server in order to access the application resources:

export access_token=$(\
    curl --insecure -X POST https://localhost:8543/auth/realms/quarkus/protocol/openid-connect/token \
    --user backend-service:secret \
    -H 'content-type: application/x-www-form-urlencoded' \
    -d 'username=alice&password=alice&grant_type=password' | jq --raw-output '.access_token' \

The example above obtains an access token for user alice.

Any user is allowed to access the http://localhost:8080/api/users/me endpoint which basically returns a JSON payload with details about the user.

curl -v -X GET \
  http://localhost:8080/api/users/me \
  -H "Authorization: Bearer "$access_token

The http://localhost:8080/api/admin endpoint can only be accessed by users with the admin role. If you try to access this endpoint with the previously issued access token, you should get a 403 response from the server.

 curl -v -X GET \
   http://localhost:8080/api/admin \
   -H "Authorization: Bearer "$access_token

In order to access the admin endpoint you should obtain a token for the admin user:

export access_token=$(\
    curl --insecure -X POST https://localhost:8543/auth/realms/quarkus/protocol/openid-connect/token \
    --user backend-service:secret \
    -H 'content-type: application/x-www-form-urlencoded' \
    -d 'username=admin&password=admin&grant_type=password' | jq --raw-output '.access_token' \

Checking Permissions Programmatically

In some cases, you may want to programmatically check whether or not a request is granted to access a protected resource. By injecting a SecurityIdentity instance in your beans, you are allowed to check permissions as follows:

import io.quarkus.security.identity.SecurityIdentity;
import io.smallrye.mutiny.Uni;

public class ProtectedResource {

    SecurityIdentity identity;

    public Uni<List<Permission>> get() {
        return identity.checkPermission(new AuthPermission("{resource_name}")).onItem()
                .transform(granted -> {
                    if (granted) {
                        return identity.getAttribute("permissions");
                    throw new ForbiddenException();

Mapping Protected Resources

By default, the extension is going to fetch resources on-demand from Keycloak where their URI are used to map the resources in your application that should be protected.

If you want to disable this behavior and fetch resources during startup, you can use the following configuration:


Note that, depending on how many resources you have in Keycloak the time taken to fetch them may impact your application startup time.

More About Configuring Protected Resources

In the default configuration, Keycloak is responsible for managing the roles and deciding who can access which routes.

To configure the protected routes using the @RolesAllowed annotation or the application.properties file, check the Using OpenID Connect Adapter to Protect JAX-RS Applications guide. For more details, check the Security guide.

Configuration Reference

The configuration is based on the official Keycloak Policy Enforcer Configuration. If you are looking for more details about the different configuration options, please take a look at this documentation,

Configuration property fixed at build time - All other configuration properties are overridable at runtime

Configuration property



Adapters will make separate HTTP invocations to the Keycloak server to turn an access code into an access token. This config option defines how many connections to the Keycloak server should be pooled



Enables policy enforcement.



Specifies how policies are enforced.

permissive, enforcing, disabled


Defines the limit of entries that should be kept in the cache



Defines the time in milliseconds when the entry should be expired



Specifies how the adapter should fetch the server for resources associated with paths in your application. If true, the policy enforcer is going to fetch resources on-demand accordingly with the path being requested



Specifies how scopes should be mapped to HTTP methods. If set to true, the policy enforcer will use the HTTP method from the current request to check whether or not access should be granted



The name of a resource on the server that is to be associated with a given path


A URI relative to the application’s context path that should be protected by the policy enforcer




An array of strings with the scopes associated with the method

list of string


A string referencing the enforcement mode for the scopes associated with a method

all, any, disabled


permissive, enforcing, disabled