I'm trying to implement a custom SAML identity provider in keycloak. The use case is that I need to be able to specify the value of Issuer in the SAML authentication request. By default you can see in SAMLIdentityProvider.java that this is currently set by: private String getEntityId(UriInfo uriInfo, RealmModel realm) { return UriBuilder.fromUri(uriInfo.getBaseUri()).path("realms").path(realm.getName()).build().toString(); } So you end up with something like: <saml:Issuer xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion"> https://mykeycloakinstance.com/auth/realms/acme</saml:Issuer> So I'm trying to extend SAMLIdentityProvider.java and SAMLIdentityProviderFactory.java and create my own. The idea being that I would add a new text field to the SAML identity provider screen where I could specify the issuer used in the authentication request. I've created a project which you can find here: https://github.com/jeff-sweetjacket/keycloak-custom-saml-idp When I drop this jar into /standalone/deployments it gets picked up and is registered without issue. However, when I try to add this new identity provider through the keycloak admin UI I get a "Resource not found..." page. Here's a relevant stackoverflow question which shows an image of the screen: https://stackoverflow.com/questions/52757115/how-to-have-identity-provide... And an associated issue on this mailing list: https://lists.jboss.org/pipermail/keycloak-user/2018-October/015828.html I've gone through the documentation for creating a custom SPI here: https://www.keycloak.org/docs/latest/server_development/#_providers But I can't find any information about how to create / modify an existing page in keycloak admin such as the add SAML identity provider page. Can anyone point me in the right direction? Thanks, Jeff