How to Sync MySQL Databases when offline?

My application that is running on a client uses a MySQL database running on a server. So multiple clients are connected to the same server. That works well when the server is online. But now I would like to enhance my application to be able to run in an offline mode. +--------------+ | | +-----------+ SERVER +----------+ | | | | | +-------+------+ | | | | +------+-------+ +-------+------+ +-------+------+ | | | | | | | Client 1 | | Client 2 | | Client X | | | | | | | +--------------+ +--------------+ +--------------+ Now comes the problem: what happens when the client is offline? I need a copy of my MySQL database on each client too. By default the application interacts with the MySQL on the server. If this server is not accessible (for what reason ever: server is offline or client has no internet connection) it should use the MySQL running on the client. If the client/server connection is available again the databases need to be synched automatically. My question is now: how to achieve this? First of all I checked the MySQL-replication, but in my scenario I have multiple "masters" and an unknown number of clients. So I afraid that replication is not my solution. Is it possible to solve my problem with MaxScale? I never worked with that so I really appreciate any help.