A custom client authenticator is installed on non-server entity. The custom client authenticator authorizes communication between a client application of a client and requested entities of a server. A native authentication technology for the client is different than a native authentication technology for the server. The custom client authenticator is registered in a descriptor file that is accessible by the server. The custom client authenticator generates an authorization token for the client. The authorization token is transmitted as part of a request message for the client application to the server. The custom client authenticator validates the authorization token on behalf of the server. The request message is forwarded to the requested entities executing on the server based on the validating.