An example application to have two applications synchronized using PHP
To get the servers started used the script start.sh which will have two separate local php servers listening to ports 8001 for the receiving end and 8000 for the sending end.
Once done open a browser at http://localhost:8000 and another one at http://localhost:8001 to see what the current database state is for both applications.
Go to http://localhost:8000/sync.php to see the results of sending the information to the receiver and refresh the screen on http://localhost:8001 to see the end result