Zappa is for deploying WSGI apps, there are tons of existing WSGI servers out there[0][1][2][3] ;)

[0] http://gunicorn.org/

[1] http://uwsgi.readthedocs.io/en/latest/

[2] http://docs.cherrypy.org/

[3] https://modwsgi.readthedocs.io/en/develop/