Custom Auth parameter

Hello, I am trying to figure out how i can pass in a parameter as part of the samlRequest, (it can be a seperate parameter) for example

and in keycloak, i want to take that custom value, and send it as part of the post request to my saml assertion endpoint. let me know if this is possible. it would be great if i could get this to work.

I definitely am able to put a custom param at the end of the saml login url, but how can i read that custom param from the url in keycloak? and thus send it back as part of the user’s attributes. thanks, any help is appreciated.


Issue found: if we use an identity broker for authentication, the uri becomes the request uri from the identity provider. then we lose our custom value.

hi, andres
i am using custom identity provider
and getting this error
Parameter annotated with PathParam cannot be null
can you tell me in which place of my code i shoud paste your issue?

public class RemoteUserStorageProviderFactory implements UserStorageProviderFactory {

public static final String PROVIDER_NAME = "username-81";

public RemoteUserStorageProvider create(KeycloakSession keycloakSession, ComponentModel componentModel) {
    return new RemoteUserStorageProvider(keycloakSession, componentModel, buildHttpClient("http://localhost:8081"));

public String getId() {
    return PROVIDER_NAME;

private UserApiService buildHttpClient(String uri) {

    ResteasyClient client = new ResteasyClientBuilder().build();
    ResteasyWebTarget target =;

    return target.proxyBuilder(UserApiService.class)