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Unlike other mod_* projects, such as mod_perl and mod_python, mod_lisp does not embed a Common Lisp interpreter in Apache. In concept it is closer to FastCGI, handling requests by serializing them into a textual representation and sending that over a socket to a persistent Common Lisp program, and then sending the Common Lisp system's response to a client. The client may be a web browser, but is more likely to be a reverse proxy server. It is this server that interacts with the user's browser.