MapChat: A super simple location based chat in about 400 lines of code  

This demo app is hosted on GitHub pages and uses a Vert.x SockJS server deployed on a single core Azure machine. This tiny lightweight Vert.x server served hundreds of concurrent users and could be scaled horizontally with very minimal effort. The whole app runs on a 0$ budget, with the server running on the free tier azure instance and the static content being hosted and served from GitHub Pages.

Vert.x, which is sometimes viewed as the Node.js for Java world, is a modern, lightweight framework to build reactive applications running on the JVM. I wanted to get into Vert.x framework, on which I heard very good impressions, by implementing something with it and this is the result. This approach (stateless reactive servers) can be upscaled by running additional vertices on the same machine, with every vertical utilizing approximately one of the server cores, or by clustering additional servers using hazelcast link.

Another very pleasant experience was working with GitHub pages. As a developer that feels comfortable working with git for any purpouse , this seems to me the easiest and fastest way to setup a small website serving static content for free! All you need to do to push new content to your website is merge it to your gh-pages branch and you have almost no need to worry about bandwidth limitations or performance issues.

Working on this micro project really showed me that much can be done with few spare hours and very few lines of code, when you have the wide selection of technologies that we as developers have today and a small focused concept.