Protect a service application by using OpenID Connect (OIDC) bearer authentication

Here, you use the Quarkus OpenID Connect (OIDC) extension to secure a Jakarta REST application using Bearer authentication. The bearer tokens are issued by OIDC and OAuth 2.0 compliant authorization servers, such as Keycloak.

To better understand OIDC Bearer authentication, see OIDC Bearer authentication.


To complete this guide, you need:

  • Roughly 15 minutes

  • An IDE

  • JDK 11+ installed with JAVA_HOME configured appropriately

  • Apache Maven 3.8.8

  • A working container runtime (Docker or Podman)

  • Optionally the Quarkus CLI if you want to use it

  • Optionally Mandrel or GraalVM installed and configured appropriately if you want to build a native executable (or Docker if you use a native container build)

  • jq tool


In this example, we build a 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.

The /api/admin endpoint is protected with RBAC (Role-Based Access Control) where only users granted with the admin role can access. At this endpoint, we use the @RolesAllowed annotation to declaratively enforce the access constraint.


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, or download an archive.

The solution is located in the security-openid-connect-quickstart directory.


Create the Maven project

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

quarkus create app org.acme:security-openid-connect-quickstart \
    --extension='oidc,resteasy-reactive-jackson' \
cd security-openid-connect-quickstart

To create a Gradle project, add the --gradle or --gradle-kotlin-dsl option.

For more information about how to install the Quarkus CLI and use it, please refer to the Quarkus CLI guide.

mvn io.quarkus.platform:quarkus-maven-plugin:3.0.4.Final:create \
    -DprojectGroupId=org.acme \
    -DprojectArtifactId=security-openid-connect-quickstart \
    -Dextensions='oidc,resteasy-reactive-jackson' \
cd security-openid-connect-quickstart

To create a Gradle project, add the -DbuildTool=gradle or -DbuildTool=gradle-kotlin-dsl option.

This command generates a Maven project, importing the oidc extension which is an implementation of OIDC for Quarkus.

If you already have your Quarkus project configured, you can add the oidc extension to your project by running the following command in your project base directory:

quarkus extension add 'oidc'
./mvnw quarkus:add-extension -Dextensions='oidc'
./gradlew addExtension --extensions='oidc'

This will add the following to your build file:


Write the application

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


import jakarta.inject.Inject;

import org.jboss.resteasy.reactive.NoCache;

public class UsersResource {

    SecurityIdentity securityIdentity;

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

    public static class User {

        private final String userName;

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

        public String getUserName() {
            return userName;

The source code for the /api/admin endpoint is also very simple. The main difference here is that we are using a @RolesAllowed annotation to make sure that only users granted with the admin role can access the endpoint:



public class AdminResource {

    public String admin() {
        return "granted";

Injection of the SecurityIdentity is supported in both @RequestScoped and @ApplicationScoped contexts.

Configure the application

Configure the Quarkus OpenID Connect (OIDC) extension by setting the following configuration properties in the src/main/resources/ file.


# Tell Dev Services for Keycloak to import the realm file
# This property is not effective when running the application in JVM or Native modes



  • %prod.quarkus.oidc.auth-server-url sets the base URL of the OpenID Connect (OIDC) server. The %prod. profile prefix ensures that Dev Services for Keycloak launches a container when you run the application in dev mode. See Running the Application in Dev mode section below for more information.

  • quarkus.oidc.client-id sets a client-id that identifies the application.

  • quarkus.oidc.credentials.secret sets the client secret, which is used by the client_secret_basic authentication method.

Start and configure the Keycloak server

Before you start with configuration, put the realm configuration file on the classpath (target/classes directory) to import it automatically when running in dev mode - unless you have already built a complete solution. In this case, the realm file is added to the classpath during the build.

Do not start the Keycloak server when you run the application in a dev mode - Dev Services for Keycloak will launch a container. See the Running the Application in Dev mode section below for more information.

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

docker run --name keycloak -e KEYCLOAK_ADMIN=admin -e KEYCLOAK_ADMIN_PASSWORD=admin -p 8180:8080{keycloak.version} start-dev

where keycloak.version should be set to 17.0.0 or higher.

You should be able to access your Keycloak Server at localhost:8180.

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.

If you want to use the Keycloak Admin Client to configure your server from your application, include the either quarkus-keycloak-admin-client or the quarkus-keycloak-admin-client-reactive (if the application uses quarkus-rest-client-reactive) extension. See the Quarkus Keycloak Admin Client guide for more information.

Run the application in Dev mode

To run the application in a dev mode, use:

quarkus dev
./mvnw quarkus:dev
./gradlew --console=plain quarkusDev

Dev Services for Keycloak will launch a Keycloak container and import a quarkus-realm.json.

Open a Dev UI available at /q/dev-v1 and click on a Provider: Keycloak link in an OpenID Connect Dev UI card.

You will be asked to log in into a Single Page Application provided by OpenID Connect Dev UI:

  • Login as alice (password: alice) who has a user role

    • accessing /api/admin will return 403

    • accessing /api/users/me will return 200

  • Logout and login as admin (password: admin) who has both admin and user roles

    • accessing /api/admin will return 200

    • accessing /api/users/me will return 200

Run the Application in JVM mode

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

First compile it:

quarkus build
./mvnw install
./gradlew build

Then run it:

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

Run the application 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:

quarkus build --native
./mvnw install -Dnative
./gradlew build -Dquarkus.package.type=native

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


Test the application

See the Running the Application in Dev mode section above about testing your application in a dev mode.

You can test the application launched in JVM or Native modes with curl.

The application is using Bearer authentication 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 http://localhost:8180/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 http://localhost:8180/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' \

Please also see the OIDC Bearer authentication, Dev Services for Keycloak section, about writing the integration tests which depend on Dev Services for Keycloak.