Client Registration CLI

Client Registration CLI is a command line interface tool that can be used by application developers to configure new clients to integrate with {book_project_name}. It is specifically designed to interact with Keycloak Client Registration REST endpoints.

It is necessary to create a new client configuration for each new application hosted on a unique hostname in order for Keycloak to be able to interact with the application (and vice-versa) and perform its function of providing a login page, SSO session management etc.

Client Registration CLI allows you to configure application clients from a command line, and can be used in shell scripts as well.

To allow a particular user to use Client Registration CLI a {book_project_name} administrator will typically use Admin Console to configure a new user, or configure a new client, and a client secret, to protect access to Client Registration REST API.

Configuring a new regular user for use with Client Registration CLI

Login as admin into Admin Console (e.g. http://localhost:8080/auth/admin). Select a realm you want to administer. If you want to use existing user, select it for edit, otherwise create a new user. Go to Role Mappings tab. Under Client Roles select realm-management. Under Available Roles select manage-client for full set of client management permissions. Alternatively you can choose view-clients for read-only or create-client for ability to create new clients. These permissions grant user the capability to perform operations without the use of Initial Access Token or Registration Access Token.

It’s possible to not assign users any of realm-management roles. In that case user can still login with Registration Client CLI but will not be able to use it without having possession of an Initial Access Token. Trying to perform any operations without it will result in 403 Forbidden error.

Administrator can issue Initial Access Tokens from Admin Console by selecting Initial Access Token tab under Realm Settings.

Configuring a client for use with Client Registration CLI

By default the Client Registration CLI identifies as admin-cli client which is automatically configured for every new realm. No additional client configuration is required when using login with a username. You may wish to strengthen security by configuring the client Access Type as Confidential, and under Credentials tab select ClientId and Secret. When running kcreg config credentials you would then also have to provide a secret e.g. by using --secret.

If you want to use a separate client configuration for Registration Client CLI then you can create a new client - for example you can call it reg-cli. When running kcreg config credentials you then need to specify a clientId to use e.g. --client reg-cli.

If you want to use a service account associated with the client, then you need to enable a service account. In Admin Client you go to Clients section, and select a client for edit. Then under Settings first change Access Type to Confidential. Then toggle Service Accounts Enabled setting to On, and Save the configuration.

Under Credentials tab you can choose to configure either Client Id and Secret, or Signed JWT.

You can now avoid specifying user when using kcreg config credentials and only provide a client secret or keystore info.

Installing Client Registration CLI

Client Registration CLI is packaged inside Keycloak Server distribution. You can find execution scripts inside bin directory.

The Linux script is called, and the one for Windows is called kcreg.bat.

In order to setup the client to be used from any location on the filesystem you may want to add Keycloak server directory to your PATH.

On Linux:


On Windows:

c:\> set PATH=%PATH%;%KEYCLOAK_HOME%\bin
c:\> kcreg

Using Client Registration CLI

Usually a user will first start an authenticated session by providing credentials, then perform some CRUD operations.

For example on Linux:

$ config credentials --server http://localhost:8080/auth --realm demo --user user --client reg-cli
$ create -s clientId=my_client -s 'redirectUris=["http://localhost:8980/myapp/*"]'
$ get my_client

Or on Windows:

c:\> kcreg config credentials --server http://localhost:8080/auth --realm demo --user user --client reg-cli
c:\> kcreg create -s clientId=my_client -s "redirectUris=[\"http://localhost:8980/myapp/*\"]"
c:\> kcreg get my_client

In a production environment Keycloak has to be accessed with https: to avoid exposing tokens to network sniffers. If server’s certificate is not issued by one of the trusted CAs that are included in Java’s default certificate truststore, then you will need to prepare a truststore.jks file, and instruct Client Registration CLI to use it.

For example on Linux:

$ config truststore --trustpass $PASSWORD ~/.keycloak/truststore.jks

Or on Windows:

c:\> kcreg config truststore --trustpass %PASSWORD% %HOMEPATH%\.keycloak\truststore.jks

Logging In

When logging in with Client Registration CLI you specify a server endpoint url, and a realm. Then you specify a username, or alternatively you can only specify a client id, which will result in special service account being used. In the first case, a password for the specified user has to be used at login. In the latter case there is no user password - only client secret or a Signed JWT is used.

Regardless of the method, the account that logs in needs to have proper permissions in order to be able to perform client registration operations. Keep in mind that any account can only have permissions to manage clients within the same realm. If you need to manage different realms, you need to configure users in different realms with permissions to manage clients.

Client Registration CLI by itself does not support configuring the users, for that you would need to use Admin Console web interface or Admin Client CLI once it’s available.

When kcreg successfully logs in it receives authorization tokens and saves them into a private config file so they can be used for subsequent invocations. See next chapter for more info on configuration file.

See built-in help for more information on using Client Registration CLI.

For example on Linux:

$ help

Or on Windows:

c:\> kcreg help

See kcreg config credentials --help for more information about starting an authenticated session.

Working with alternative configurations

By default, Client Registration CLI automatically maintains a configuration file at a default location - .keycloak/kcreg.config under user’s home directory.

You can use --config option at any time to point to a different file / location. This way you can mantain multiple authenticated sessions in parallel. It is safest to perform operations tied to a single config file from a single thread.

Make sure to not make a config file visible to other users on the system as it contains access tokens, and secrets that should be kept private.

You may want to avoid storing any secrets at all inside a config file for the price of less convenience and having to do more token requests. In that case you can use --no-config option with all your commands. You will have to specify all authentication info with each kcreg invocation.

Initial Access and Registration Access Tokens

Client Registration CLI can be used by developers who don’t have an account configured at Keycloak server they want to use. That’s possible when realm administrator issues developer an Initial Access Token. It is up to realm administrator to decide how to issue and distribute these tokens. Admin can limit an Initial Access Token by maximum age, and a total number of clients that can be created with it. Many Initial Access Tokens can be created, and it’s up to realm administrator to distribute them.

Once a developer is in possession of Initial Access Token they can use it to create new clients without authenticating with kcreg config credentials. Rather, Initial Access Token can be stored in configuration, or specified as part of kcreg create command.

For example on Linux:

$ config initial-token $TOKEN
$ create -s clientId=myclient


$ create -s clientId=myclient -t $TOKEN

On Windows:

c:\> kcreg config initial-token %TOKEN%
c:\> kcreg create -s clientId=myclient


c:\> kcreg create -s clientId=myclient -t %TOKEN%

When Initial Access Token is used, the server response will include a newly issued Registration Access Token for client that was just created. Any subsequent operation for that client needs to be performed by authenticating with that token.

Client Registration CLI automatically uses its private configuration file to save, and make use of this token for each created client. As long as the same configuration file is used for all client operations, the developer will not need to authenticate in order to read, update, or delete a client they created.

You can read more about Initial Access and Registration Access Tokens in Client Registration chapter.

See kcreg config initial-token --help and kcreg config registration-token --help for more information on how to configure them with Client Registration CLI.

Performing CRUD operations

After authenticating with credentials or configuring Initial Access Token, the first operation will usually be to create a new client.

We’ve seen the simplest command to create a new client already. Often we may want to use a prepared JSON file as a template, and set / override some of the attributes. For example, this is how you read a JSON file in default client configuration format, override any clientId it may contain with a new one, override / set any other attributes as well, and after successful creation print the new client configuration to standard output.

On Linux:

$ create -s clientId=myclient -f client-template.json -s baseUrl=/myclient -s 'redirectUris=["/myclient/*"]' -o

On Windows:

C:\> kcreg create -s clientId=myclient -f client-template.json -s baseUrl=/myclient -s "redirectUris=[\"/myclient/*\"]" -o

See kcreg create --help for more information about kcreg create.

You can use kcreg attrs to list the available attributes. Note, that many configuration attributes are not checked for validity or consistency. It is up to you to specify proper values. Also note, that you should not have any id fields in your template or specify them as arguments to kcreg create.

Once a new client is created you can retrieve it again by using kcreg get.

On Linux:

$ get myclient

On Windows:

C:\> kcreg get myclient

You can also get an adapter configuration which you can drop into your web application in order to integrate with Keycloak server.

On Linux:

$ get myclient -e install

On Windows:

C:\> kcreg get myclient -e install

See kcreg get --help for more information about kcreg get.

It’s simple to update client configurations as well. There are two modes of updating.

One is to submit a complete new state to the server after getting current configuration, saving it into a file, editing it, and posting it back.

On Linux:

$ get myclient > myclient.json
$ vi myclient.json
$ update myclient -f myclient.json

On Windows:

C:\> kcreg get myclient > myclient.json
C:\> notepad myclient.json
C:\> kcreg update myclient -f myclient.json

Another is to get current client, set or delete fields on it, and post it back all in one single step.

On Linux:

$ update myclient -s enabled=false -d redirectUris

On Windows:

C:\> kcreg update myclient -s enabled=false -d redirectUris

You can even use a file that contains only changes to be applied so you don’t have to specify too many values as arguments. In this case we specify --merge to tell Client Registration CLI that rather than treating mychanges.json as full new configuration, it should see it as a set of attributes to be applied over existing configuration.

On Linux:

$ update myclient --merge -d redirectUris -f mychanges.json

On Windows:

C:\> kcreg update myclient --merge -d redirectUris -f mychanges.json

See kcreg update --help for more information about kcreg update.

You may sometimes also need to delete a client.

On Linux:

$ delete myclient

On Windows:

C:\> kcreg delete myclient

See kcreg delete --help for more information about kcreg delete.

Refreshing Invalid Registration Access Tokens

When performing CRUD operation using no-config mode Client Registration CLI can no longer handle Registration Access Tokens for you. In that case it is possible to lose track of most recently issued Registration Access Token for a client, which makes it impossible to perform any further CRUD operations on that client without using credentials of an account with 'manage-clients' permissions.

If you have permissions you can reissue a new Registration Access Token for the client, and have it printed to stdout or saved to a config file of your choice. If not you have to ask realm administrator to reissue a new Registration Access Token for your client, and send it to you. You can then use the token by passing it to any CRUD command via --token option. You can also use kcreg config registration-token command to save the new token in configuration file, and have Client Registration CLI automatically handle it for you from that point on.

See kcreg update-token --help for more information about kcreg update-token.


  • Q: When logging in I get an error: Parameter client_assertion_type is missing [invalid_client]

    A: Your client is configured with Signed JWT token credentials which means you have to use --keystore parameter when logging in.