A client token is generated for a client process in response to a client token request. An authentication request including the client token is received from a client endpoint associated with the client process. The client endpoint is authenticated, including generating and providing an endpoint token to the client endpoint. A first mapping between the client token and transport channels used for messages received from the client process and a second mapping between the client endpoint and the client token are generated. A first message is received over a first transport channel from the client endpoint, the message including the client token and the endpoint token. A response to the first message is sent to the client endpoint over a second transport channel, without re-authenticating the client endpoint, the second transport channel being different than the first transport channel and being selected based on the first and second mappings.