Hello, As far as I understand the decoder API it is mostly geared towards defining the decoder for an entire snippet in one place. I would like to know what the recommended way is to separate the definition of the decoder over separate modules. The semantics of my incoming messages are thus: object: - "type": string denoting the type - "payload": type-specific payload I want to create a decoder that only extracts the type and uses that to determine which decoder to send the payload to. Then it continues with whatever lisp object the decoder returned. What I thought would be appropriate is to create a generic function; (defgeneric json->data (type payload)) and then simply register decoders as follows: (defmethod json->data ((type (eq :foo)) payload) "Decode message of type foo." ...) (defmethod json->data ((type (eq :bar)) payload) "Decode message of type bar." ...) But now I am not really sure how to glue this together. What would you recommend? Is this the right frame of mind at all or should I take a totally different approach? Thanks! Hraban