Suggestions for the technologies to be used for realtime whiteboard application

I am trying to build realtime whiteboard application where about 50 users connect at a same time on a canvas and do stuff (just like awwapp.com). I am currently using PHP Ratchet websocket library with canvasJS for canvas library.

My question is, what technology will be best for creating this?

My Requirements:

• Realtime Connection between 50 users at a time.


• Should work on Hosting like DigitalOcean


• Low Cost (I don't want to spend money for a real time server like pusher)


• Better connectivity with Database


• Fallback support for older browsers.


• Less pain to create and maintain.

Note: I am a PHP developer but learning NodeJS too for realtime system.

What are your suggestions for the technology i should use.

Some Technologies I came across:

• PHP with Ratchet and Mysql


• NodeJS with Socket.io


• PHP with Comet


• PHP with Elephant.io


• NodeJS with SockJS

For Database:

• MySQL


• NOSQL

I know this is a very broad question but please tell me your thoughts.

For reference on what I want to build:

• awwapp.com


• tutorsbox.com