git clone 'https://github.com/hankhero/cl-json.git'
CL-JSON provides an encoder of Lisp objects to JSON format and a corresponding decoder of JSON data to Lisp objects. Both the encoder and the decoder are highly customizable; at the same time, the default settings ensure a very simple mode of operation, similar to that provided by YASON or ST-JSON. CL-JSON is well tested and the automated testcases includes the JSON_checker tests.
Documentation is at the project page on common-lisp.net.