Before you must know, what is the chat application & How it works?<p>Build application like Slack, Hipchat(Server-side database):<p>where the messages sent are stored in the server database. This results in the storage of a vast amount of data in the server-side data storage.<p>On the other hand,<p>Build Application like Whatsapp, Viber(Client-side database):<p>It is quite effective in minimizing the data stored in the database by holding the data within the device & diminishing the queuing of messages and consumption of data.<p>For more: <a href="https://blog.mirrorfly.com/real-time-chat-server-database-for-storing-messages/" rel="nofollow">https://blog.mirrorfly.com/real-time-chat-server-database-fo...</a>