By default, the Deki Wiki API listens on port 8081. For example, if you'd like the API to listen on port 9999 do the following:
Edit the /etc/dekiwiki/mindtouch.host.conf file and change the following variable:
HTTP_PORT=9999
Note: On windows, you'll need to edit your bin/mindtouch.host.bat file and change the http-port argument to http-port 9999
Edit the LocalSettings.php file in your Deki Wiki web root and add the following variable:
$wgDreamServer = 'http://localhost:9999';